Augite

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Augite

Augite is a single chain inosilicate

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....
mineral

Mineral

A mineral is a naturally occurring solid formed through Geology processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties....
described chemically as (Ca,Mg,Fe)SiO₃ or 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 ....
magnesium

Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, atomic weight 24.3050 and common oxidation number +2.Magnesium, an alkaline earth metal, is the ninth most abundance of the chemical elements in the universe by mass....
iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
silicate

Silicate

A silicate is a compound containing an anion 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 consist of silicon with oxygen as the ligand...
. The 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....
s are monoclinic and prismatic. Augite has two prominent prismatic cleavages, meeting at angles near 90°.

Augite is a solid solution

Solid solution

A solid solution is a solid-phase solution of one or more soluble in a solvent. Such a mixture is considered a solution rather than a Chemical compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the mixture remains in a single wiktionary:Homogeneous phase ....
in the pyroxene

Pyroxene

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

Diopside

Diopside is a monoclinic pyroxene mineral with composition MgCaSi2O6. It forms complete solid solution series with hedenbergite and augite, and partial solid solutions with orthopyroxene and pigeonite....
and hedenbergite

Hedenbergite

Hedenbergite, calciumironsilicon2oxygen6, is the iron rich end member of the pyroxene group having a monoclinic crystal system....
are important endmembers in augite, but augite can also contain significant 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....
, titanium

Titanium

Titanium is a chemical element with the symbol Ti and atomic number 22. Sometimes called the ?space age metal?, it has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver colour....
, and sodium

Sodium

Sodium is an element which has the symbol Na , atomic number 11, atomic mass 23 amu , and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" ....
and other elements. The calcium content of augite is limited by a miscibility gap between it and pigeonite

Pigeonite

Pigeonite is a mineral in the clinopyroxene group. It has a general formula of Silicon2Oxygen6 The calcium cation fraction can vary from 5% to 25%, with iron and magnesium making up the rest of the cations....
and orthopyroxene: when occurring with either of these other pyroxenes, the calcium content of augite is a function of temperature and pressure, but mostly of temperature, and so can be useful in reconstructing temperature histories of rocks.

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Encyclopedia

Augite is a single chain inosilicate

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....
mineral

Mineral

Calcium

Magnesium

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
silicate

Silicate

Crystal

Solid solution

Pyroxene

Diopside

Hedenbergite

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....
, titanium

Titanium

Sodium

Pigeonite

Omphacite

Omphacite is a member of the pyroxene group of silicate minerals with formula: silicon2oxygen6. It is a variably deep to pale green or nearly colorless variety of pyroxene....
, but this gap occurs at lower temperature and is not well understood.

It is found in igneous rock

Igneous rock

Igneous rock is one of the three main Rock types . Igneous rock is formed by magma being cooled and becoming solid . They may form with or without crystallization, either below the surface as Intrusion rocks or on the surface as extrusive rocks....
s; for example, gabbro

Gabbro

Gabbro refers to a large group of dark, coarse-grained, intrusive igneous rock chemically equivalent to basalt. The rocks are Intrusive, formed when molten magma is trapped beneath the Earth's surface and cools into a crystalline mass....
and basalt

Basalt

Basalt is a common extrusive volcanic rock. It is usually gray to black and fine-grained due to rapid cooling of lava at the surface of a planet....
. It also occurs in relatively high-temperature metamorphic rock

Metamorphic rock

Metamorphic rock is the result of the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form"....
s such as 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"....
granulite

Granulite

Granulites are fine to medium?grained metamorphic rocks that have experienced high temperatures of metamorphism, composed mainly of feldspars sometimes associated with quartz and anhydrous mafic, with granoblastic texture and gneissose to massive structure....
.

Occasional specimens have a shiny appearance that give rise to the mineral's name, which is from the Greek augites, meaning "brightness", although ordinary specimens have a dull (dark green, brown or black) finish.