Home      Discussion      Topics      Dictionary      Almanac
Signup       Login
Mineral

Mineral

Overview
A mineral is a naturally occurring solid formed through geological
Geology
Geology is the science and study of the solid and liquid matter that constitutes the Earth. The field of geology encompasses the study of the composition, structure, physical properties, dynamics, and history of Earth materials, and the processes by which they are formed, moved, and changed...

 processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties. A rock
Rock (geology)
In geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

, by comparison, is an aggregate of minerals and/or mineraloids
Mineraloid
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under...

, and need not have a specific chemical composition. Minerals range in composition from pure elements
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons.Common examples of elements...

 and simple salts to very complex silicate
Silicate
A silicate is a compound containing an ion in which one or more central silicon atoms are surrounded by electronegative ligands. This definition is broad enough to include species such as hexafluorosilicate , [SiF6]2−, but the silicate species that are encountered most often...

s with thousands of known forms. The study of minerals is called mineralogy
Mineralogy
Mineralogy is an Earth Science focused around the chemistry, crystal structure, and physical properties of minerals. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their...

.


To be classified as a true mineral, a substance must be a solid
Solid
Matter is generally found in three different forms: solid, liquid, and gas . The solid state of matter is characterized by a distinct structural rigidity and resistance to deformation . Most solids have high values both of Young's modulus and of the shear modulus of elasticity...

 and have a crystalline structure.
Discussion
Ask a question about 'Mineral'
Start a new discussion about 'Mineral'
Answer questions from other users
Full Discussion Forum
 
Unanswered Questions
Recent Discussions
Encyclopedia
A mineral is a naturally occurring solid formed through geological
Geology
Geology is the science and study of the solid and liquid matter that constitutes the Earth. The field of geology encompasses the study of the composition, structure, physical properties, dynamics, and history of Earth materials, and the processes by which they are formed, moved, and changed...

 processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties. A rock
Rock (geology)
In geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

, by comparison, is an aggregate of minerals and/or mineraloids
Mineraloid
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under...

, and need not have a specific chemical composition. Minerals range in composition from pure elements
Chemical element
A chemical element is a pure chemical substance consisting of one type of atom distinguished by its atomic number, which is the number of protons in its nucleus. The term is also used to refer to a pure chemical substance composed of atoms with the same number of protons.Common examples of elements...

 and simple salts to very complex silicate
Silicate
A silicate is a compound containing an ion in which one or more central silicon atoms are surrounded by electronegative ligands. This definition is broad enough to include species such as hexafluorosilicate , [SiF6]2−, but the silicate species that are encountered most often...

s with thousands of known forms. The study of minerals is called mineralogy
Mineralogy
Mineralogy is an Earth Science focused around the chemistry, crystal structure, and physical properties of minerals. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their...

.

Mineral definition and classification


To be classified as a true mineral, a substance must be a solid
Solid
Matter is generally found in three different forms: solid, liquid, and gas . The solid state of matter is characterized by a distinct structural rigidity and resistance to deformation . Most solids have high values both of Young's modulus and of the shear modulus of elasticity...

 and have a crystalline structure. It must also be a naturally occurring, homogeneous substance with a defined chemical composition. Traditional definitions excluded organically derived material. However, the International Mineralogical Association
International Mineralogical Association
The International Mineralogical Association is an international group of 38 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 4000 plus known mineral species...

 in 1995 adopted a new definition:
a mineral is an element or chemical compound that is normally crystalline and that has been formed as a result of geological processes.


The modern classifications include an organic class – in both the new Dana and the Strunz
Strunz classification
Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz in his 1941 Mineralogische Tabellen....

 classification schemes.

The chemical composition may vary between end member
Endmember (mineralogy)
An endmember in mineralogy is a mineral that is at the extreme end of a mineral series in terms of purity. Minerals often can be described as solid solutions with varying compositions of some chemical elements, rather than as substances with an exact chemical formula...

s of a mineral system. For example the plagioclase
Plagioclase
Plagioclase is a very important series of tectosilicate minerals within the feldspar family. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series...

 feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s comprise a continuous series from sodium
Sodium
Sodium is a metallic element with a symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals within "group 1"...

 and silicon-rich albite
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. As such it represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula NaAlSi3O8. It is a tectosilicate...

 (NaAlSi3O8) to calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft grey alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust...

 and aluminium-rich anorthite
Anorthite
Anorthite is a compositional variety of plagioclase feldspar. Plagioclase is an abundant mineral in the Earth's crust. The formula of pure anorthite is CaAl2Si2O8.-Mineralogy :...

 (CaAl2Si2O8) with four recognized intermediate compositions between. Mineral-like substances that don't strictly meet the definition are sometimes classified as mineraloid
Mineraloid
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under...

s. Other natural-occurring substances are nonmineral
Nonmineral
A nonmineral is a substance found in a natural environment that does not satisfy the definition of a mineral and is not even a mineraloid...

s. Industrial minerals
Industrial minerals
Industrial minerals are geological materials which are mined for their commercial value, which are not fuel and are not sources of metals ....

 is a market term and refers to commercially valuable mined materials (see also Minerals and Rocks section below).

A crystal structure
Crystal structure
In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms or molecules in a crystalline liquid or solid. A crystal structure is composed of a motif, a set of atoms arranged in a particular way, and a lattice exhibiting long-range order and symmetry...

is the orderly geometric spatial arrangement of atom
Atom
The atom is a basic unit of matter consisting of a dense, central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

s in the internal structure of a mineral. There are 14 basic crystal lattice arrangements of atoms in three dimensions, and these are referred to as the 14 "Bravais lattice
Bravais lattice
In geometry and crystallography, a Bravais lattice, studied by , is an infinite set of points generated by a set of discrete translation operations described by:...

s". Each of these lattices can be classified into one of the seven crystal
Crystal
A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is crystallography...

 systems, and all crystal structures currently recognized fit in one Bravais lattice and one crystal system. This crystal structure is based on regular internal atomic or ion
Ion
An ion is an atom or molecule where the total number of electrons is not equal to the total number of protons, giving it a net positive or negative electrical charge...

ic arrangement that is often expressed in the geometric form that the crystal takes. Even when the mineral grains are too small to see or are irregularly shaped, the underlying crystal structure is always periodic and can be determined by X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 10 to 0.01 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays...

 diffraction.
Chemistry and crystal structure together define a mineral. In fact, two or more minerals may have the same chemical composition, but differ in crystal structure (these are known as polymorphs). For example, pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold due to its resemblance to gold...

 and marcasite
Marcasite
The mineral marcasite, sometimes called white iron pyrite, is iron sulfide . Marcasite is often mistakenly confused with pyrite, but marcasite is lighter and more brittle. Specimens of marcasite often crumble and break up due to the unstable crystal structure, and it is this crystal structure that...

 are both iron sulfide, but their arrangement of atoms differs. Similarly, some minerals have different chemical compositions, but the same crystal structure: for example, halite
Halite
Halite is the mineral form of sodium chloride, NaCl, commonly known as rock salt. Halite forms isometric crystals. The mineral is typically colorless to yellow, but may also be light blue, dark blue, and pink depending on the amount and type of impurities...

 (made from sodium and chlorine
Chlorine
Chlorine Chlorine Chlorine ( , from the Greek word 'χλωρóς' (khlôros, meaning 'pale green'), is the chemical element with atomic number 17 and symbol Cl. It is a halogen, found in the periodic table in group 17 (formerly VII, VIIa, or VIIb). As the chloride ion, which is part of common salt and...

), galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

 (made from lead
Lead
Lead is a main-group element with symbol Pb and atomic number 82. Lead is a soft, malleable poor metal, also considered to be one of the heavy metals. Lead has a bluish-white color when freshly cut, but tarnishes to a dull grayish color when exposed to air...

 and sulfur
Sulfur
Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant, multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element and as sulfide and sulfate minerals...

) and periclase
Periclase
Periclase occurs naturally in contact metamorphic rocks and is a major component of most basic refractory bricks. It is a cubic form of magnesium oxide ....

 (made from magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12 and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the earth's crust by mass, although ninth in the Universe as a whole...

 and oxygen
Oxygen
Oxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...

) all share the same cubic crystal structure.

Crystal structure greatly influences a mineral's physical properties. For example, though diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is the second most stable form of carbon, after graphite; however, the conversion rate from diamond to graphite is...

 and graphite
Graphite
The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Greek γραφειν : "to draw/write", for its use in pencils, where it is commonly called lead, as distinguished from the actual metallic element lead...

 have the same composition (both are pure carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

), graphite is very soft, while diamond is the hardest of all known minerals. This happens because the carbon atoms in graphite are arranged into sheets which can slide easily past each other, while the carbon atoms in diamond form a strong, interlocking three-dimensional network.

There are currently more than 4,000 known minerals, according to the International Mineralogical Association
International Mineralogical Association
The International Mineralogical Association is an international group of 38 national societies. The goal is to promote the science of mineralogy and to standardize the nomenclature of the 4000 plus known mineral species...

, which is responsible for the approval of and naming of new mineral species found in nature. Of these, perhaps 100 can be called "common", 50 are "occasional", and the rest are "rare" to "extremely rare".

Differences between minerals and rocks


A mineral is a naturally occurring solid with a definite chemical composition and a specific crystalline structure. A rock
Rock (geology)
In geology, rock is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

 is an aggregate of one or more minerals. (A rock may also include organic remains and mineraloid
Mineraloid
A mineraloid is a mineral-like substance that does not demonstrate crystallinity. Mineraloids possess chemical compositions that vary beyond the generally accepted ranges for specific minerals. For example, obsidian is an amorphous glass and not a crystal. Jet is derived from decaying wood under...

s.) Some rocks are predominantly composed of just one mineral. For example, limestone
Limestone
Limestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geologic record...

 is a sedimentary rock
Sedimentary rock
Sedimentary rock is the type of rock that is formed by sedimentation of material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral and/or organic particles to settle and accumulate or minerals to precipitate from a solution....

 composed almost entirely of the mineral calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 470°C, and vaterite is even less stable....

. Other rocks contain many minerals, and the specific minerals in a rock can vary widely. Some minerals, like quartz
Quartz
Quartz is the second most abundant mineral in the Earth's continental crust . It is made up of a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2.There are many different varieties of...

, mica
Mica
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition...

 or feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

 are common, while others have been found in only four or five locations worldwide. The vast majority of the rocks of the Earth's crust consist of quartz, feldspar, mica, chlorite
Chlorite group
The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....

, kaolin, calcite, epidote
Epidote
Epidote is a calcium aluminium iron sorosilicate mineral, Ca2Al2O, crystallizing in the monoclinic system. Well-developed crystals are of frequent occurrence: they are commonly prismatic in habit, the direction of elongation being perpendicular to the single plane of symmetry...

, olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4...

, augite
Augite
Augite is a single chain inosilicate mineral described chemically as SiO3 or calcium magnesium iron silicate. The crystals are monoclinic and prismatic. Augite has two prominent prismatic cleavages, meeting at angles near 90°....

, hornblende
Hornblende
Hornblende is a complex inosilicate series of minerals . Hornblende is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. It is an isomorphous mixture of three molecules; a calcium-iron-magnesium silicate, an...

, magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name ferrous-ferric oxide...

, hematite
Hematite
Hematite, also spelled as hæmatite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

, limonite
Limonite
Limonite is an ore consisting in a mixture of hydrated iron oxide-hydroxide of varying composition. The generic formula is frequently written as FeO·nH2O, although this is not entirely accurate as limonite often contains a varying amount of oxide compared to hydroxide.Together with...

 and a few other minerals. Over half of the mineral species known are so rare that they have only been found in a handful of samples, and many are known from only one or two small grains.

Commercially valuable minerals and rocks are referred to as industrial minerals
Industrial minerals
Industrial minerals are geological materials which are mined for their commercial value, which are not fuel and are not sources of metals ....

. Rocks from which minerals are mined
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, vein or seam. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock salt and potash...

 for economic purposes are referred to as ores
Orés
Orés is a municipality in the Cinco Villas, in the province of Zaragoza, in the autonomous community of Aragon, Spain. It belongs to the comarca of Cinco Villas. It is placed 104 km to the northwest of the provincial capital city, Zaragoza. Its coordinates are: 42° 17' N, 1° 00' W, and is located...

 (the rocks and minerals that remain, after the desired mineral has been separated from the ore, are referred to as tailings
Tailings
Tailings are the materials left over after the process of separating the valuable fraction from the worthless fraction of an ore....

).

Mineral composition of rocks


A main determining factor in the formation of minerals in a rock mass is the chemical composition of the mass, for a certain mineral can be formed only when the necessary elements are present in the rock. Calcite is most common in limestone
Limestone
Limestone is a sedimentary rock composed largely of the mineral calcite . The deposition of limestone strata is often a by-product and indicator of biological activity in the geologic record...

s, as these consist essentially of calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the chemical formula CaCO3. It is a common substance found in rock in all parts of the world, and is the main component of shells of marine organisms, snails, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural...

; quartz is common in sandstones and in certain igneous rocks which contain a high percentage of silica.

Other factors are of equal importance in determining the natural association or paragenesis
Paragenesis
Paragenesis is a petrologic concept meaning an equilibrium assemblage of mineral phases. It is used in studies of igneous and metamorphic rock genesis and importantly in studies of the hydrothermal deposition of ore minerals and the rock alteration associated with ore mineral deposits...

 of rock-forming minerals, principally the mode of origin of the rock and the stages through which it has passed in attaining its present condition. Two rock masses may have very much the same bulk composition and yet consist of entirely different assemblages of minerals. The tendency is always for those compounds to be formed which are stable under the conditions under which the rock mass originated. A granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite has a medium to coarse texture, occasionally with some individual crystals larger than the groundmass forming a rock known as porphyry. Granites can be pink to dark gray or even black, depending on their...

 arises by the consolidation of a molten magma
Magma
Magma [from Greek μάγμα, paste] is molten rock that is found beneath the surface of the Earth, and may also exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma often collects in a magma chamber inside a volcano...

 at high temperatures and great pressures and its component minerals are those stable under such conditions. Exposed to moisture, carbonic acid
Carbonic acid
Carbonic acid has the formula H2CO3. It is also a name sometimes given to solutions of carbon dioxide in water, which contain small amounts of H2CO3. The salts of carbonic acids are called bicarbonates and carbonates. It is a weak acid...

 and other subaerial agents at the ordinary temperatures of the Earth's surface, some of these original minerals, such as quartz and white mica are relatively stable and remain unaffected; others weather
Weathering
Weathering is the decomposition of Earth's rocks, soils and minerals through direct contact with the planet's atmosphere. Weathering occurs in situ, or "with no movement", and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice,...

 or decay and are replaced by new combinations. The feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

 passes into kaolinite
Kaolinite
Kaolinite is a clay mineral with the chemical composition Al2Si2O54. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra...

, muscovite
Muscovite
Muscovite is a phyllosilicate mineral of aluminium and potassium with formula KAl22, or 236...

 and quartz, and any mafic
Mafic
Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron; the term was derived by contracting "magnesium" and "ferric". Most mafic minerals are dark in color and the relative density is greater than 3. Common rock-forming mafic minerals include olivine,...

 minerals such as pyroxene
Pyroxene
The pyroxenes are a group of important rock-forming silicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...

s, amphibole
Amphibole
Amphibole defines an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain SiO4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles crystallize into two crystal systems,...

s or biotite
Biotite
Biotite is a common phyllosilicate mineral within the mica group, with the approximate chemical formula K3AlSi3O102. More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the...

 have been present they are often altered to chlorite
Chlorite group
The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....

, epidote
Epidote
Epidote is a calcium aluminium iron sorosilicate mineral, Ca2Al2O, crystallizing in the monoclinic system. Well-developed crystals are of frequent occurrence: they are commonly prismatic in habit, the direction of elongation being perpendicular to the single plane of symmetry...

, rutile
Rutile
Rutile is a mineral composed primarily of titanium dioxide, TiO2.Rutile is the most common natural form of TiO2. Two rarer polymorphs of TiO2 are known:...

 and other substances. These changes are accompanied by disintegration, and the rock falls into a loose, incoherent, earthy mass which may be regarded as a sand or soil. The materials thus formed may be washed away and deposited as sandstone or siltstone. The structure of the original rock is now replaced by a new one; the mineralogical constitution is profoundly altered; but the bulk chemical composition may not be very different. The sedimentary rock may again undergo metamorphism
Metamorphism
Metamorphism is the solid-state recrystallization of pre-existing rocks due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids. Both mineralogical, chemical and crystallographic changes can occur during this process.Three types...

. If penetrated by igneous rocks it may be recrystallized or, if subjected to enormous pressures with heat and movement during mountain building
Orogeny
Orogeny refers to natural mountain building, and may be studied as a tectonic structural event, as a geographical event, and a chronological event...

, it may be converted into a gneiss
Gneiss
Gneiss is a common and widely distributed type of rock formed by high-grade regional metamorphic processes from pre-existing formations that were originally either igneous or sedimentary rocks. Gneissic rocks are usually medium to coarse foliated and largely recrystallized but do not carry large...

 not very different in mineralogical composition though radically different in structure to the granite which was its original state.

Physical properties of minerals


Classifying minerals can range from simple to very difficult. A mineral can be identified by several physical properties, some of them being sufficient for full identification without equivocation. In other cases, minerals can only be classified by more complex chemical or X-ray diffraction analysis; these methods, however, can be costly and time-consuming.

Physical properties commonly used are:
  • Crystal structure and habit: See the above discussion of crystal structure. A mineral may show good crystal habit or form, or it may be massive, granular or compact with only microscopically visible crystals.



  • Hardness: the physical hardness of a mineral is usually measured according to the Mohs scale
    Mohs scale of mineral hardness
    The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German mineralogist Friedrich Mohs and is one of several definitions of hardness in materials science...

    . This scale is relative and goes from 1 to 10. Minerals with a given Mohs hardness can scratch the surface of any mineral that has a lower hardness than itself.
    • Mohs hardness scale
      Mohs scale of mineral hardness
      The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German mineralogist Friedrich Mohs and is one of several definitions of hardness in materials science...

      :
  1. Talc
    Talc
    Talc is a mineral composed of hydrated magnesium silicate with the chemical formula H2Mg34 or Mg3Si4O102. In loose form, it is the widely used substance known as talcum powder...

     Mg3Si4O10(OH)2
  2. Gypsum
    Gypsum
    Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O.-Crystal varieties:...

     CaSO4·2H2O
  3. Calcite
    Calcite
    Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 470°C, and vaterite is even less stable....

     CaCO3
  4. Fluorite
    Fluorite
    Fluorite is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon. Cubic crystals up to 20 cm across have been found at Dalnegorsk, Russia...

     CaF2
  5. Apatite
    Apatite
    Apatite is a group of phosphate minerals, usually referring to hydroxyapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH, F, Cl or...

     Ca5(PO4)3(OH,Cl,F)
  6. Orthoclase
    Orthoclase
    Orthoclase is an important tectosilicate mineral which forms igneous rock. The name is from the Greek for "straight fracture," because its two cleavage planes are at right angles to each other. An alternate name is alkali feldspar...

     KAlSi3O8
  7. Quartz
    Quartz
    Quartz is the second most abundant mineral in the Earth's continental crust . It is made up of a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2.There are many different varieties of...

     SiO2
  8. Topaz
    Topaz
    Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO42. Topaz crystallizes in the orthorhombic system and its crystals are mostly prismatic terminated by pyramidal and other faces....

     Al2SiO4(OH,F)2
  9. Corundum
    Corundum
    Corundum is a crystalline form of aluminium oxide with traces of iron, titanium and chromium. It is a rock-forming mineral. It is one of the naturally clear transparent materials, but can have different colors when impurities are present...

     Al2O3
  10. Diamond
    Diamond
    In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is the second most stable form of carbon, after graphite; however, the conversion rate from diamond to graphite is...

     C (pure carbon)

  • Luster indicates the way a mineral's surface interacts with light and can range from dull to glassy (vitreous).
    • Metallic -high reflectivity like metal: galena
      Galena
      Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

       and pyrite
      Pyrite
      The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold due to its resemblance to gold...

    • Sub-metallic -slightly less than metallic reflectivity: magnetite
      Magnetite
      Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name ferrous-ferric oxide...

    • Non-metallic lusters:
      • Adamantine – brilliant, the luster of diamond
        Diamond
        In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is the second most stable form of carbon, after graphite; however, the conversion rate from diamond to graphite is...

         also cerussite
        Cerussite
        Cerussite is a mineral consisting of lead carbonate , and an important ore of lead. The name is from the Latin cerussa, white lead. Cerussa nativa was mentioned by Conrad Gessner in 1565, and in 1832 F. S. Beudant applied the name cruse to the mineral, whilst the present form, cerussite, is due to W...

         and anglesite
        Anglesite
        Anglesite is a lead sulfate mineral, PbSO4. It occurs as an oxidation product of primary lead sulfide ore, galena. Anglesite occurs as prismatic orthorhombic crystals and earthy masses, and is isomorphous with barite and celestine. It has a high specific gravity of 6.3 due to its lead...

      • Vitreous -the luster of a broken glass: quartz
      • Pearly – iridescent and pearl-like: talc and apophyllite
        Apophyllite
        The name apophyllite refers to a specific group of phyllosilicates, a class of minerals that also includes the micas. Originally, the group name referred to a specific mineral, but was redefined in 1978 to stand for a class of minerals of similar chemical makeup that comprise a solid solution...

      • Resinous – the luster of resin: sphalerite
        Sphalerite
        Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...

         and sulfur
        Sulfur
        Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant, multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element and as sulfide and sulfate minerals...

      • Silky – a soft light shown by fibrous materials: gypsum and chrysotile
        Chrysotile
        Chrysotile or white asbestos is the most commonly encountered form of asbestos, accounting for approximately 95% of the asbestos in place in the United States and a similar proportion in other countries. It is a soft, fibrous silicate mineral in the serpentine group of phyllosilicates: as such, it...

      • Dull/earthy - shown by finely crystallized minerals: the kidney ore variety of hematite
        Hematite
        Hematite, also spelled as hæmatite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...


  • Color
    Color
    Color or colour is the visual perceptual property corresponding in humans to the categories called red, yellow, blue and others. Color derives from the spectrum of light interacting in the eye with the spectral sensitivities of the light receptors...

    indicates the appearance of the mineral in reflected light or transmitted light for translucent minerals (i.e. what it looks like to the naked eye).
    • Iridescence – the play of colors due to surface or internal interference. Labradorite
      Labradorite
      Labradorite , a feldspar mineral, is an intermediate to calcic member of the plagioclase series. It is usually defined as having "%An" between 50 and 70. The specific gravity ranges from 2.71 to 2.74. The streak is white, like most silicates. The refractive index ranges from 1.555 to 1.575....

       exhibits internal iridescence whereas hematite and sphalerite often show the surface effect.
  • Streak
    Streak (mineralogy)
    The streak of a mineral is the color of the powder produced when it is dragged across an unweathered surface. Unlike the apparent color of a mineral, which for most minerals can vary considerably, the trail of finely ground powder generally has a more consistent characteristic color, and is thus...

    refers to the color of the powder a mineral leaves after rubbing it on an unglazed porcelain streak plate. Note that this is not always the same color as the original mineral.
  • Cleavage
    Cleavage (crystal)
    Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the...

    describes the way a mineral may split apart along various planes. In thin sections, cleavage is visible as thin parallel lines across a mineral.
  • Fracture
    Fracture
    A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal. Sometimes, in crystalline materials, individual crystals...

    describes how a mineral breaks when broken contrary to its natural cleavage planes.
    • Chonchoidal fracture is a smooth curved fracture with concentric ridges of the type shown by glass.
    • Hackley is jagged fracture with sharp edges.
    • Fibrous
    • Irregular
  • Specific gravity relates the mineral mass
    Mass
    In physics, mass commonly refers to any of three properties of matter, which have been shown experimentally to be equivalent: inertial mass, active gravitational mass and passive gravitational mass...

     to the mass of an equal volume of water, namely the density
    Density
    The density of a material is defined as its mass per unit volume. The symbol of density is ρ .- Formula :Mathematically:where: is the density, is the mass, is the volume....

     of the material. While most minerals, including all the common rock-forming minerals, have a specific gravity of 2.5–3.5, a few are noticeably more or less dense, e.g. several sulfide minerals have high specific gravity compared to the common rock-forming minerals.
  • Other properties: fluorescence
    Fluorescence
    Fluorescence is the emission of visible light by a substance that has absorbed light of a differing, usually invisible, wavelength. Absorption of a photon triggers the emission of a photon with a longer wavelength. A shorter wavelength emission is sometimes observed from multiple photon absorption...

     (response to ultraviolet light), magnetism
    Magnetism
    In physics, the term magnetism is used to describe how materials respond on the microscopic level to an applied magnetic field; to categorize the magnetic phase of a material. For example, the most well known form of magnetism is ferromagnetism such that some ferromagnetic materials produce their...

    , radioactivity, tenacity (response to mechanical induced changes of shape or form), piezoelectricity
    Piezoelectricity
    Piezoelectricity is the ability of some materials to generate an electric field or electric potential in response to applied mechanical stress. The effect is closely related to a change of polarization density within the material's volume...

     and reactivity to dilute acid
    Acid
    An acid is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a hydrogen ion activity greater than in pure water, i.e. a pH less than 7.0...

    s.

Chemical properties of minerals


Minerals may be classified according to chemical composition. They are here categorized by anion group. The list below is in approximate order of their abundance in the Earth's crust
Crust (geology)
In geology, a crust is the outermost solid shell of a rocky planet or moon, which is chemically distinct from the underlying mantle. The crusts of Earth, our Moon, Mercury, Venus, Mars, Io, and other planetary bodies have been generated largely by igneous processes, and these crusts are richer in...

. The list follows the Dana
James Dwight Dana
James Dwight Dana was an American geologist, mineralogist and zoologist. He made important studies of mountain-building, volcanic activity, and the origin and structure of continents and oceans....

 classification system which closely parallels the Strunz classification
Strunz classification
Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz in his 1941 Mineralogische Tabellen....

.

Silicate class


The largest group of minerals by far are the silicates
Silicate minerals
The silicate minerals make up the largest and most important class of rock-forming minerals, comprising approximately 90 percent of the crust of the Earth. They are classified based on the structure of their silicate group...

(most rocks are ≥95% silicates), which are composed largely of silicon
Silicon
Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. A tetravalent metalloid, silicon is less reactive than its chemical analog carbon...

 and oxygen
Oxygen
Oxygen Oxygen Oxygen (acid, literally "sharp", from the taste of acids) and -γενής (-genēs) (producer, literally begetter) is the element with atomic number 8 and represented by the symbol O...

, with the addition of ions such as aluminium
Aluminium
Aluminium or aluminum is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13. It is not soluble in water under normal circumstances....

, magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12 and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the earth's crust by mass, although ninth in the Universe as a whole...

, iron
Iron
Iron is a metallic chemical element with the symbol Fe and atomic number 26. Iron is a group 8 and period 4 element and is therefore classified as a transition metal. Iron and iron alloys are by far the most common metals and the most common ferromagnetic materials in everyday use...

, and calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft grey alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust...

. Some important rock-forming silicates include the feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s, quartz
Quartz
Quartz is the second most abundant mineral in the Earth's continental crust . It is made up of a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2.There are many different varieties of...

, olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4...

s, pyroxene
Pyroxene
The pyroxenes are a group of important rock-forming silicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...

s, amphibole
Amphibole
Amphibole defines an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain SiO4 tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Amphiboles crystallize into two crystal systems,...

s, garnet
Garnet
The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. The name "garnet" may come from either the Middle English word gernet meaning 'dark red', or the Latin granatus , possibly a reference to the Punica granatum , a plant with red seeds...

s, and mica
Mica
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic with a tendency towards pseudo-hexagonal crystals and are similar in chemical composition...

s.

Carbonate class


The carbonate minerals
Carbonate minerals
Carbonate minerals are those minerals containing the carbonate ion: CO32-.-Anhydrous carbonates:*Calcite group: Trigonal**Calcite CaCO3**Gaspeite CO3**Magnesite MgCO3...

consist of those minerals containing the anion (CO3)2- and include calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 470°C, and vaterite is even less stable....

 and aragonite
Aragonite
Aragonite is a carbonate mineral, one of the two common, naturally occurring polymorphs of calcium carbonate, CaCO3. The other polymorph is the mineral calcite. Aragonite's crystal lattice differs from that of calcite, resulting in a different crystal shape, an orthorhombic system with...

 (both calcium carbonate), dolomite
Dolomite
Dolomite is the name of a sedimentary carbonate rock and a mineral, both composed of calcium magnesium carbonate CaMg2 found in crystals....

 (magnesium/calcium carbonate) and siderite
Siderite
Siderite is also the name of a type of iron meteorite.----Siderite is a mineral composed of iron carbonate FeCO3. It takes its name from the Greek word sideros, “iron”. It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus...

 (iron carbonate). Carbonates are commonly deposited in marine settings when the shells of dead plankton
Plankton
Plankton consist of any drifting organisms that inhabit the pelagic zone of oceans, seas, or bodies of fresh water. Plankton are defined by their ecological niche rather than their phylogenetic or taxonomic classification...

ic life settle and accumulate on the sea floor. Carbonates are also found in evaporitic
Evaporite
Evaporites are water-soluble mineral sediments that result from the evaporation of bodies of surficial water. Evaporites are considered sedimentary rocks.- Formation of evaporite rocks :...

 settings (e.g. the Great Salt Lake
Great Salt Lake
Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt lake in the western hemisphere, the fourth-largest terminal lake in the world, and the 37th-largest lake on Earth. In an average year the lake covers an area of around , but the lake's size fluctuates...

, Utah
Utah
Utah is a western state of the United States. It was the 45th state admitted to the Union, on January 4, 1896. Approximately 80 percent of Utah's 2,736,424 people live along the Wasatch Front, centering around Salt Lake City. In contrast, vast expanses of the state are nearly uninhabited, making...

) and also in karst
KARST
Kilometer-square Area Radio Synthesis Telescope is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors on karst landforms, which are bowlshaped limestone sinkholes named after a Yugoslavian geologist Karst. It will consist of about 30 individual...

 regions, where the dissolution and reprecipitation of carbonates leads to the formation of cave
Cave
A cave or cavern is a natural underground void large enough for a human to enter. Some people suggest that the term cave should only apply to cavities that have some part that does not receive daylight; however, in popular usage, the term includes smaller spaces like sea caves, rock shelters, and...

s, stalactite
Stalactite
A stalactite is a type of speleothem that hangs from the ceiling or wall of limestone caves. It is a type of dripstone.- Formation and type:...

s and stalagmite
Stalagmite
A stalagmite is a type of speleothem that rises from the floor of a limestone cave due to the dripping of mineralized solutions and the deposition of calcium carbonate. The corresponding formation on the ceiling of a cave is known as a stalactite...

s. The carbonate class also includes the nitrate
Nitrate
In inorganic chemistry, a nitrate is a salt of nitric acid with an ion composed of one nitrogen and three oxygen atoms . In organic chemistry the esters of nitric acid and various alcohols are called nitrates.-Chemical properties:...

 and borate mineral
Borate mineral
The borate minerals are minerals which contain a borate anion group. The borate units may be polymerised similar to the SiO4 unit of the silicate mineral class...

s.

Sulfate class


Sulfate mineral
Sulfate mineral
The sulfate mineral class are those minerals which include the sulfate ion within their structure. The sulfate minerals occur commonly in primary evaporite depositional environments, as gangue minerals in hydrothermal veins and as secondary minerals in the oxidizing zone of sulfide mineral deposits...

s
all contain the sulfate anion, SO42-. Sulfates commonly form in evaporitic
Evaporite
Evaporites are water-soluble mineral sediments that result from the evaporation of bodies of surficial water. Evaporites are considered sedimentary rocks.- Formation of evaporite rocks :...

 settings where highly saline waters slowly evaporate, allowing the formation of both sulfates and halides at the water-sediment interface. Sulfates also occur in hydrothermal vein systems as gangue minerals along with sulfide
Sulfide
A sulfide is a chemical compound containing sulfur in its lowest oxidation number of −2.- Properties :...

 ore
Ore
An ore is a type of rock that contains minerals such as gemstones or metals that can be extracted through mining and refined for use. Samples of ore in the form of exceptionally beautiful crystals, exotic layering visible when sectioned or polished or metallic presentations such as large nuggets or...

 minerals. Another occurrence is as secondary oxidation products of original sulfide minerals. Common sulfates include anhydrite
Anhydrite
Anhydrite is a mineral - anhydrous calcium sulfate, CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium and strontium sulfates, as might be expected from...

 (calcium sulfate), celestine (strontium sulfate), barite
Barite
Baryte, or barite, is a mineral consisting of barium sulfate. The baryte group consists of baryte, celestine, anglesite and anhydrite. Baryte itself is generally white or colorless, and is the main source of barium...

 (barium sulfate), and gypsum
Gypsum
Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO4·2H2O.-Crystal varieties:...

 (hydrated calcium sulfate). The sulfate class also includes the chromate
Chromate
Chromates and dichromates are salts of chromic acid and dichromic acid, respectively. Chromate salts contain the chromate anion, CrO, and usually have an intense yellow color. Dichromate salts contain the dichromate anion, Cr2O, and usually have an intense orange color...

, molybdate
Molybdate
In chemistry a molybdate is a compound containing an oxoanion with molybdenum in its highest oxidation state of 6. Molybdenum can form a very large range of such oxoanions which can be discrete structures or polymeric extended structures, although the latter are only found in the solid state.The...

, selenate
Selenate
The selenate ion is SeO42−.Selenates are analogous to sulfates and have similar chemistry. They are highly soluble in aqueous solutions at ambient temperatures....

, sulfite
Sulfite
Sulfites are compounds that contain the sulfite ion SO . The sulfite ion is the conjugate base of sulfurous acid. Although the acid itself is elusive, its salts are widely used.-Structure:...

, tellurate
Tellurate
The tellurate ion is TeO42− or TeO66−.Unlike sulfate, tellurate is a somewhat good oxidizer; it can be reduced to tellurite or tellurium....

, and tungstate
Tungstate
In chemistry a tungstate is a compound that contains an oxoanion of tungsten or is a mixed oxide containing tungsten. The simplest tungstate ion is WO42−, "orthotungstate"...

 minerals.

Halide class



The halide mineral
Halide mineral
The halide mineral class include those minerals with a dominant halide anion .Examples include:*Halite NaCl*Sylvite KCl*Chlorargyrite AgCl and bromargyrite AgBr...

s
are the group of minerals forming the natural salt
Salt
A salt, in chemistry, is an ionic compound, and can result from the neutralization reaction of acids and bases. Salts are ionic compounds composed of cations and anions so that the product is electrically neutral...

s and include fluorite
Fluorite
Fluorite is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon. Cubic crystals up to 20 cm across have been found at Dalnegorsk, Russia...

 (calcium fluoride), halite
Halite
Halite is the mineral form of sodium chloride, NaCl, commonly known as rock salt. Halite forms isometric crystals. The mineral is typically colorless to yellow, but may also be light blue, dark blue, and pink depending on the amount and type of impurities...

 (sodium chloride), sylvite
Sylvite
Sylvite is potassium chloride in natural mineral form. It forms crystals in the isometric system very similar to normal rock salt, halite ....

 (potassium chloride), and sal ammoniac
Sal ammoniac
Sal ammoniac is a rare mineral composed of ammonium chloride, NH4Cl. It forms colorless to white to yellow-brown crystals in the isometric-hexoctahedral class. It has very poor cleavage and a brittle to conchoidal fracture. It is quite soft, with a Mohs hardness of 1.5 to 2, and has a...

 (ammonium chloride). Halides, like sulfates, are commonly found in evaporite
Evaporite
Evaporites are water-soluble mineral sediments that result from the evaporation of bodies of surficial water. Evaporites are considered sedimentary rocks.- Formation of evaporite rocks :...

 settings such as playa lake
Playa
A playa is a dry or ephemeral lakebed, generally extending to the shore, or a remnant of an endorheic lake. Such flats consist of fine-grained sediments infused with alkali salts. Playas are also known as alkali flats, sabkhas, dry lakes or mud flats...

s and landlocked seas such as the Dead Sea
Dead Sea
The Dead Sea is a salt lake in Jordan to the east and in the West Bank and Israel to the west. Its surface and shores are below sea level, the lowest elevation on the Earth's surface on dry land. The Dead Sea is deep, the deepest hypersaline lake in the world. It is also one of the world's...

 and Great Salt Lake
Great Salt Lake
Great Salt Lake, located in the northern part of the U.S. state of Utah, is the largest salt lake in the western hemisphere, the fourth-largest terminal lake in the world, and the 37th-largest lake on Earth. In an average year the lake covers an area of around , but the lake's size fluctuates...

. The halide class includes the fluoride
Fluoride
Fluoride is the anion F, the reduced form of fluorine. Both organic and inorganic compounds containing the element fluorine are sometimes called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are distinct relative to other...

, chloride
Chloride
The chloride ion is formed when the element chlorine picks up one electron to form an anion Cl...

, bromide
Bromide
A bromide ion is a bromine atom with charge of −1.Compounds with bromine in formal oxidation state −1 are called bromides, and each individual chemical in this class can be called a bromide, as well...

 and iodide
Iodide
An iodide ion is an iodine atom with a −1 charge. Compounds with iodine in formal oxidation state −1 are called iodides. This can include ionic compounds such as caesium iodide or covalent compounds such as phosphorus triiodide. This is the same naming scheme as is seen with chlorides...

 minerals.

Oxide class


Oxide mineral
Oxide mineral
The oxide mineral class includes those minerals in which the oxide anion is bonded to one or more metal ions. The hydroxide bearing minerals are typically included in the oxide class...

s
are extremely important in mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, vein or seam. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock salt and potash...

 as they form many of the ores
Orés
Orés is a municipality in the Cinco Villas, in the province of Zaragoza, in the autonomous community of Aragon, Spain. It belongs to the comarca of Cinco Villas. It is placed 104 km to the northwest of the provincial capital city, Zaragoza. Its coordinates are: 42° 17' N, 1° 00' W, and is located...

 from which valuable metals can be extracted. They also carry the best record of changes in the Earth's magnetic field
Earth's magnetic field
Earth's magnetic field is approximately a magnetic dipole, with the magnetic field S pole near the Earth's geographic north pole and the other magnetic field N pole near the Earth's geographic south pole...

. They commonly occur as precipitates close to the Earth's surface, oxidation products of other minerals in the near surface weathering
Weathering
Weathering is the decomposition of Earth's rocks, soils and minerals through direct contact with the planet's atmosphere. Weathering occurs in situ, or "with no movement", and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice,...

 zone, and as accessory minerals in igneous rocks of the crust and mantle
Mantle (geology)
The mantle is a part of an astronomical object. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core. Earth's mantle is about 2,970 km thick rocky shell that...

. Common oxides include hematite
Hematite
Hematite, also spelled as hæmatite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...

 (iron oxide), magnetite
Magnetite
Magnetite is a ferrimagnetic mineral with chemical formula Fe3O4, one of several iron oxides and a member of the spinel group. The chemical IUPAC name is iron oxide and the common chemical name ferrous-ferric oxide...

 (iron oxide), chromite
Chromite
Chromite is iron magnesium chromium oxide: Cr2O4. It is an oxide mineral belonging to the spinel group. Magnesium can substitute for iron in variable amounts; also, aluminium and ferric iron commonly substitute for chromium....

 (iron chromium oxide), spinel
Spinel
The spinels are any of a class of minerals of general formulation A2+B23+O42- which crystallise in the cubic crystal system, with the oxide anions arranged in a cubic close-packed lattice and the cations A and B occupying some or all of the...

 (magnesium aluminium oxide – a common component of the mantle), ilmenite
Ilmenite
Ilmenite is a weakly magnetic titanium-iron oxide mineral which is iron-black or steel-gray. It is a crystalline iron titanium oxide . It crystallizes in the trigonal system, and it has the same crystal structure as corundum and hematite....

 (iron titanium oxide), rutile
Rutile
Rutile is a mineral composed primarily of titanium dioxide, TiO2.Rutile is the most common natural form of TiO2. Two rarer polymorphs of TiO2 are known:...

 (titanium dioxide), and ice
Ice
Ice is a solid phase, usually crystalline, of a non-metallic substance that is liquid or gas at room temperature, such as carbon dioxide ice , ammonia ice, or methane ice. However, the predominant use of the term ice is for water ice, technically restricted to one of the 15 known crystalline phases...

 (hydrogen oxide). The oxide class includes the oxide and the hydroxide
Hydroxide
In chemistry, hydroxide is the name for the diatomic anion OH, consisting of oxygen and hydrogen atoms, usually derived from the dissociation of a base. It is one of the simplest diatomic ions known....

 minerals.

Sulfide class


Many sulfide mineral
Sulfide mineral
A sulfide mineral is a mineral containing sulfide as the major anion. Sulfides are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts.Common or important...

s
are economically important as metal ore
Ore
An ore is a type of rock that contains minerals such as gemstones or metals that can be extracted through mining and refined for use. Samples of ore in the form of exceptionally beautiful crystals, exotic layering visible when sectioned or polished or metallic presentations such as large nuggets or...

s. Common sulfides include pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold due to its resemblance to gold...

 (iron sulfide – commonly known as fools' gold), chalcopyrite
Chalcopyrite
Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2....

 (copper iron sulfide), pentlandite
Pentlandite
Pentlandite is an iron-nickel sulfide, 9S8. Pentlandite usually has a Ni:Fe ratio of close to 1:1. It also contains minor cobalt. It is named after the Irish scientist Joseph Barclay Pentland , who first noted the mineral.Pentlandite forms isometric crystals, but is normally...

 (nickel iron sulfide), and galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

 (lead sulfide). The sulfide class also includes the selenide
Selenide
A selenide is a chemical compound in which selenium serves as an anion with oxidation number of −2 , much as sulfur does in a sulfide. The chemistry of the selenides parallels that of the sulfides....

s, the telluride
Telluride (chemistry)
The telluride ion is Te2−. It is the final stable member of the series of dianions O2−, S2−, and Se2− ....

s, the arsenide
Arsenide
An arsenide ion is an arsenic atom with three extra electrons and charge −3.An arsenide is a compound with arsenic in oxidation state −3.-Examples:* sodium arsenide * gallium arsenide...

s, the antimonide
Antimonide
Antimonides are compounds of antimony with more electropositive elements. The antimonide ion is Sb3−....

s, the bismuthinides, and the sulfosalts (sulfur and a second anion such as arsenic).

Phosphate class


The phosphate mineral group actually includes any mineral with a tetrahedral unit AO4 where A can be phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus is commonly found in inorganic phosphate rocks. Elemental phosphorus exists in two major forms - white phosphorus and red phosphorus...

, antimony
Antimony
Antimony is a chemical element with the symbol Sb and atomic number 51. A metalloid, antimony has four allotropic forms. The stable form of antimony is a blue-white metalloid. Yellow and black antimony are unstable non-metals...

, arsenic
Arsenic
Arsenic is the chemical element that has the symbol As, atomic number 33 and atomic mass 74.92. Arsenic was first documented by Albertus Magnus in 1250. Arsenic is a notoriously poisonous metalloid with many allotropic forms, including a yellow and several black and grey forms...

 or vanadium
Vanadium
Vanadium is the chemical element with the symbol V and atomic number 23. It is a soft, silvery grey, ductile transition metal. The formation of an oxide layer stabilizes the metal against oxidation. Andrés Manuel del Río discovered vanadium in 1801 by analyzing the mineral vanadinite, and named it...

. By far the most common phosphate is apatite
Apatite
Apatite is a group of phosphate minerals, usually referring to hydroxyapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH, F, Cl or...

 which is an important biological
Biology
Biology is the natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy...

 mineral found in teeth and bones of many animals. The phosphate class includes the phosphate, arsenate
Arsenate
The arsenate ion is AsO43−.An arsenate is any compound that contains this ion.The arsenic atom in arsenate has a valency of 5 and is also known as pentavalent arsenic or As[V]....

, vanadate
Vanadate
In chemistry a vanadate is a compound containing an oxoanion of vanadium generally in its highest oxidation state of +5. The simplest vanadate ion is the tetrahedral, orthovanadate, VO43− anion, which is present in e.g. sodium orthovanadate and in solutions of...

, and antimonate
Antimonate
The antimonate ion is Sb6, where Sb is antimony and is the hydroxyl group.An antimonate refers to a compound that contains the antimonate ion.See category for a list...

 minerals.

Element class


The elemental group includes metals and intermetallic elements (gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. It has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is...

, silver
Silver
Silver is a chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...

, copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29.It is a ductile metal with very high thermal and electrical conductivity. Pure copper is rather soft and malleable and a freshly-exposed surface has a pinkish or peachy color...

), semi-metals
Semimetal
A semimetal is a material with a small overlap in the energy of the conduction band and valence bands.However, the bottom of the conduction band is typically situated in a different part of momentum space than the top of the valence band...

 and non-metals (antimony
Antimony
Antimony is a chemical element with the symbol Sb and atomic number 51. A metalloid, antimony has four allotropic forms. The stable form of antimony is a blue-white metalloid. Yellow and black antimony are unstable non-metals...

, bismuth
Bismuth
Bismuth is a chemical element that has the symbol Bi and atomic number 83. This trivalent poor metal chemically resembles arsenic and antimony. Bismuth is heavy and brittle; it has a silvery white color with a pink tinge owing to the surface oxide. Bismuth is the most naturally diamagnetic of all...

, graphite
Graphite
The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Greek γραφειν : "to draw/write", for its use in pencils, where it is commonly called lead, as distinguished from the actual metallic element lead...

, sulfur
Sulfur
Sulfur or sulphur is the chemical element that has the atomic number 16. It is denoted with the symbol S. It is an abundant, multivalent non-metal. Sulfur, in its native form, is a yellow crystalline solid. In nature, it can be found as the pure element and as sulfide and sulfate minerals...

). This group also includes natural alloys, such as electrum
Electrum
Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals. It has also been produced artificially. The ancient Greeks called it 'gold' or 'white gold', as opposed to 'refined gold'. Its color ranges from pale to bright yellow, depending on the...

 (a natural alloy of gold and silver), phosphides, silicide
Silicide
A silicide is a compound that has silicon with more electropositive elements.Silicon is more electropositive than carbon. Silicides are structurally closer to borides than to carbides....

s, nitrides and carbides (which are usually only found naturally in a few rare meteorites).

Organic class


The organic mineral class includes biogenic substances in which geological processes have been a part of the genesis or origin of the existing compound. Minerals of the organic class include various oxalates, mellitates, citrates, cyanate
Cyanate
The cyanate ion is an anion consisting of one oxygen atom, one carbon atom, and one nitrogen atom, [OCN], in that order, and possesses 1 unit of negative charge, borne mainly by the nitrogen atom...

s, acetates, formates, hydrocarbons and other miscellaneous species.
Examples include whewellite
Whewellite
Whewellite is a mineral, hydrated calcium oxalate, formula CaC2O4·H2O. Because of its organic content it is thought to have an indirect biological origin and this is supported by it being found in coal and sedimentary nodules. However, it has also been found...

, moolooite
Moolooite
Moolooite is a rare blue-green mineral with the formula Cu++·n . It was discovered by Richard M Clarke and Ian R Williams in Bunbury Well, Mooloo Downs station, Murchison, Western Australia in 1986...

, mellite
Mellite
Mellite, also called honeystone, is an unusual mineral being also an organic chemical. Chemically identified as an aluminium salt of mellitic acid; that is, aluminium benzene hexacarboxylate hydrate, with the chemical formula Al2C66·16H2O.It is a...

, fichtelite
Fichtelite
Fichtelite is a rare white mineral found in fossilized wood from Bavaria. It crystallizes in the monoclinic crystal system. It is a cyclic hydrocarbon dimethyl-isopropyl-perhydrophenanthrene, C19H34. It is very soft with a Mohs hardness of 1, the same as talc...

, carpathite
Carpathite
Carpathite is a rare hydrocarbon mineral. It is the mineral form of the polycyclic aromatic hydrocarbon coronene with formula: C24H12....

, evenkite and abelsonite
Abelsonite
Abelsonite, synonym nickel porphyrin, is a mineral of nickel, carbon, hydrogen, and nitrogen with formula: NiC31H32N4. It forms purple to reddish brown triclinic crystals. The crystals are soft, with a Mohs scale rating is 2 to 3...

.

See also


  • A list of minerals with associated Wikipedia articles
  • A comprehensive list of minerals
  • Dietary mineral
    Dietary mineral
    Dietary minerals are the chemical elements required by living organisms, other than the four elements carbon, hydrogen, nitrogen, and oxygen present in common organic molecules...

  • Industrial minerals
    Industrial minerals
    Industrial minerals are geological materials which are mined for their commercial value, which are not fuel and are not sources of metals ....

  • Mineral processing
    Mineral processing
    Mineral processing, otherwise known as mineral dressing, is the practice of beneficiating valuable minerals from their ores.Industrial mineral treatment processes usually combine a number of unit operations in order to liberate and separate minerals by exploiting the differences in physical...

  • Mineral water
    Mineral water
    Mineral water is water containing minerals or other dissolved substances that alter its taste or give it therapeutic value. Salts, sulfur compounds, and gases are among the substances that can be dissolved in the water. Mineral water can often be effervescent. Mineral water can be prepared or can...

  • Mineral wool
    Mineral wool
    Mineral wool, also known as mineral fibres or man-made mineral fibres are fibres made from natural or synthetic minerals or metal oxides. The latter term is generally used to refer solely to synthetic materials including fibreglass, ceramic fibres and rock or stone wool...


  • Mining
    Mining
    Mining is the extraction of valuable minerals or other geological materials from the earth, usually from an ore body, vein or seam. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock salt and potash...

  • Norman L. Bowen
    Norman L. Bowen
    Norman Levi Bowen was born in Kingston, Ontario, Canada June 21, 1887 and died on September 11, 1956. Bowen "revolutionized experimental petrology and our understanding of mineral crystallization...

  • Ore
    Ore
    An ore is a type of rock that contains minerals such as gemstones or metals that can be extracted through mining and refined for use. Samples of ore in the form of exceptionally beautiful crystals, exotic layering visible when sectioned or polished or metallic presentations such as large nuggets or...

    s
  • Quarry
    Quarry
    A quarry is a type of open-pit mine from which rock or minerals are extracted. Quarries are generally used for extracting building materials, such as dimension stone, construction aggregate, riprap, sand, and gravel...

  • Rocks
  • Strunz classification
    Strunz classification
    Strunz classification is a scheme for categorizing minerals based upon their chemical composition, introduced by German mineralogist Karl Hugo Strunz in his 1941 Mineralogische Tabellen....

  • Tucson Gem & Mineral Show
    Tucson Gem & Mineral Show
    The Tucson Gem, Mineral & Fossil Showcase is one of the premier gem and mineral shows in the world. The event takes place annually in late January and February at approximately 40 to 49 different locations across the city of Tucson, Arizona. Most of the shows are open to the public, except for...



External links