Biotite

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Biotite

Biotite is a common phyllosilicate

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....
within the 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....
group, with the approximate chemical formula K(Mg, Fe)₃AlSi₃O₁₀(F, OH)₂. More generally, it refers to the dark mica series, primarily a solid-solution series between the iron-endmember annite, and the magnesium-endmember phlogopite

Phlogopite

Phlogopite is a yellow, greenish, or reddish-brown member of the mica family of silicate minerals. It is also known as magnesium mica.Phlogopite is the magnesium endmember of the biotite solid solution series, with the chemical formula potassiummagnesium3aluminumsilicon3oxygen102, or 2<...
; more aluminous endmembers include siderophyllite

Siderophyllite

Siderophyllite is a rare member of the mica group of silicate minerals with formula KFe++AlO102.The mineral occurs in nepheline syenite pegmatites and granite and aplite greisens....
.

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In which chemicale this biotite is soluble ?

The mension chemicales viz magnesim ,aluminium, potasium. flourine, silicon etc. Are they present i...

Encyclopedia

Biotite is a common phyllosilicate

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

Mica

Phlogopite

Siderophyllite

Siderophyllite is a rare member of the mica group of silicate minerals with formula KFe++AlO102.The mineral occurs in nepheline syenite pegmatites and granite and aplite greisens....
. Biotite was named by J.F.L. Hausmann

Johann Friedrich Ludwig Hausmann

Johann Friedrich Ludwig Hausmann , Germany mineralogist, was born in Hanover.He was educated in G?ttingen, where he obtained the degree of Ph.D....
in 1847 in honour of the French

France

France , officially the French Republic , is a country whose Metropolitan France is located in Western Europe and that also comprises various Overseas departments and territories of France....
physicist

Physicist

A physicist is a scientist who studies or practices physics. Physicists study a wide range of physical phenomena in many Physics#Major fields of physics spanning all length scales: from atom particles of which all ordinary matter is made to the behavior of the material Universe as a whole ....
Jean-Baptiste Biot

Jean-Baptiste Biot

Jean-Baptiste Biot was a France physicist, astronomer and mathematician who established the reality of meteorite....
, who, in 1816, researched the optical properties of mica

Mica

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...
. Iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bond together by potassium ions. It is sometimes called "iron mica" because it is more iron-rich than phlogopite. It is also sometimes called "black mica" as opposed to "white mica" (muscovite

Muscovite

Muscovite is a Silicate minerals mineral of aluminium and potassium with formula potassiumaluminum22, or 236....
) -- both form in some rocks, in some instances side-by-side.

Properties

Like other 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....
minerals, biotite has a highly perfect basal cleavage, and consists of flexible sheets, or lamellae

Lamellae (materials)

A lamella is a gill-shaped structure: fine sheets of material held adjacent to one another, with fluid in-between-. They appear in biology and engineering contexts, such as filter s and heat exchangers....
, which easily flake off. It has a monoclinic crystal system

Monoclinic crystal system

In crystallography, the monoclinic crystal system is one of the 7 lattice point groups. A crystal system is described by three Vector . In the monoclinic system, the crystal is described by vectors of unequal length, as in the orthorhombic system....
, with tabular to prismatic crystals with an obvious pinacoid termination. It has four prism faces and two pinacoid faces to form a pseudohexagonal crystal. Although not easily seen because of the cleavage and sheets, fracture is uneven. It has a hardness

Mohs scale of mineral hardness

Not to be confused with Siemens_#Mho, a unit of electric conductance.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....
of 2.5–3, a specific gravity

Specific gravity

Specific gravity is defined as the ratio of the density of a given solid or liquid substance to the density of water at a specific temperature and pressure, typically at 4?C and , making it a dimensionless quantity ....
of 2.7–3.1, and an average density of 3.09 g/cm³. It appears greenish to brown or black, and even yellow when weathered. It can be transparent to opaque, has a vitreous to pearly luster, and a grey-white streak. When biotite is found in large chunks, they are called “books” because it resembles a book with pages of many sheets.

Occurrence

Biotite is found in a wide variety of igneous

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....
and metamorphic rocks. For instance, biotite occurs in the lava

Lava

Lava is molten Rock expelled by a volcano during an eruption. When first expelled from a volcanic vent, it is a liquid at temperatures from 700 ?C to 1,200 ?C ....
of Mount Vesuvius

Mount Vesuvius

Mount Vesuvius is an stratovolcano east of Naples Italy. It is the only volcano on the European mainland to have erupted within the last hundred years, although it is not currently eruption....
and in the Monzoni inrusive complex of the western Dolomites

Dolomites

The Dolomites are a section of the Alps. They are located for the most part in the province of Province of Belluno, the rest in the provinces of Province of Bolzano-Bozen and Province of Trento ....
. It is an essential phenocryst

Phenocryst

A phenocryst is a relatively large and usually conspicuous crystal distinctly larger than the grains of the rock Matrix of a porphyritic igneous rock....
in some varieties of lamprophyre

Lamprophyre

Lamprophyres are uncommon, small volume ultrapotassic igneous rocks igneous rocks primarily occurring as Dike , lopoliths, laccoliths, stocks and small intrusions....
. Biotite is occasionally found in large cleavable crystals, especially in pegmatite

Pegmatite

Pegmatite is a very coarse-grained igneous rock that has a grain size of 20 mm or more; such rocks are referred to as pegmatitic.Most pegmatites are composed of quartz, feldspar and mica; in essence a "granite"....
veins, as in New England

New England

New England is a region of the United States located in the northeastern corner of the country, bounded by the Atlantic Ocean, Canada and New York State, and consisting of the modern U.S....
, Virginia

Virginia

The Commonwealth of Virginia is an United States U.S. state on the East Coast of the United States of the Southern United States. The state is known as the "Old Dominion" and sometimes as "Mother of Presidents", because it is the birthplace of Lists of United States Presidents by place of birth#By state....
and North Carolina

North Carolina

North Carolina is a U.S. state located on the Atlantic Seaboard in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north....
. Other notable occurrences include Bancroft

Bancroft, Ontario

Bancroft is a town located on the York River in Hastings County, Ontario in the Canadian province of Ontario....
and Sudbury, Ontario

Ontario

Ontario is a Provinces and territories of Canada located in the Central Canada part of Canada, the largest by population and second largest, after Quebec, in total area....
. It is an essential constituent of many metamorphic schist

Schist

The schists form a group of Erins metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, Chlorite group, talc, hornblende, graphite, and others....
s, and it forms in suitable compositions over a wide range of pressure and temperature.

Uses

Biotite is used extensively to constrain ages of rocks, by either potassium-argon dating

Potassium-argon dating

Potassium-argon dating or K-Ar dating is a radiometric dating method used in geochronology and archeology. It is based on measuring the products of the radioactive decay of potassium , which is a common element found in materials such as micas, clay minerals, tephra, and evaporites....
or argon-argon dating

Argon-argon dating

Argon-argon dating is a radiometric dating method invented to supersede Potassium-argon dating in accuracy. In this technique, the Radioactive decay of 40Potassium to 40Argon* is used to date Geology events, particularly the eruption and cooling of igneous rocks and minerals....
. Because argon escapes readily from the biotite crystal structure at high temperatures, these methods may provide only minimum ages for many rocks. Biotite is also useful in assessing temperature histories of metamorphic rocks, because the partitioning of 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....
and 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....
between biotite and 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" comes from the Latin language granatus , possibly a reference to the Punica granatum , a plant with red seeds similar in shape, size, and color to some garnet crystals....
is sensitive to temperature.

Biotite is used in electrical devices, usually as a dielectric

Dielectric

A dielectric is a nonconducting substance, i.e. an Insulator . The term was coined by William Whewell in response to a request from Michael Faraday....
in capacitors and thermionic valves.