Biotite Properties
| Chemical Composition | Biotite is K (Mg,Fe)3AlSi3O10 (OH)2 Pota ... |
| Color | Biotite is typically brown to black whil ... |
| Cleavage | Single perfect cleavage to produce thin ... |
| Hardness | 2.5 to 3 (soft) |
| Specific Gravity | Phlogopite is 2.7 (feels ‘light’), the m ... |
...
| Biotite | |
|---|---|
| Formula (repeating unit) | K(Mg,Fe) 3(AlSi 3O 10)(F,OH) 2 |
| IMA symbol | Bt |
| Crystal system | Monoclinic |
| Crystal class | Prismatic (2/m) (same H-M symbol) |
What is the chemical formula for biotite?
- ⓘ Cancrinite-bearing-alkali-feldspar-syenite
- ⓘ Nepheline-bearing-alkali-feldspar-syenite ⓘ Pulaskite
- ⓘ Sodalite-bearing-alkali-feldspar-syenite
What is biotite used for?
Biotite, like Muscovite, is a very poor conductor of heat and electricity, and is thus used as an insulator for various electrical products and semiconductors. Biotite is found in abundance worldwide, but collectors specimens are not common and come from few localities.
Is biotite a silicate or nonsilicate mineral?
In this regard, is biotite a silicate mineral? Biotite, also called black mica, a silicate mineral in the common mica group. It is abundant in metamorphic rocks (both regional and contact), in pegmatites, and also in granites and other intrusive igneous rocks.
What do muscovite and biotite have in common?
What do biotite and muscovite have in common? 15. What do muscovite and biotite have in common? How do they differ? They are both micas with layered (sheet-silicate), internal, crystalline structures and one direction of perfect cleavage. What is Muscovite stone? Muscovite is the most common form of Mica, an important mineral in sedimentary ...
What are the chemical properties of biotite?
Physical Properties of BiotiteChemical ClassificationDark micaDiagnostic PropertiesDark color, perfect cleavageChemical CompositionK(Mg,Fe)3(AlSi3O10)(F,OH)2Crystal SystemMonoclinic8 more rows
What is the empirical formula for biotite?
Biotite Mineral DataGeneral Biotite InformationChemical Formula:K(Mg,Fe++)3[AlSi3O10(OH,F)2Empirical Formula:KMg2.5Fe2+0.5AlSi3O10(OH)1.75F0.25Environment:Granitic rocks. Forms a series with phlogopite. Has several polytypes (1M, 3T, 2M1). Biotite is now a group name for phlogopite, siderophyllite and eastonite.119 more rows
What minerals are in biotite?
It's a soft mineral, with a Mohs hardness of 2.5 to 3 for biotite. Biotite forms sheets of iron, silicon, magnesium, aluminum, and hydrogen weakly bonded by potassium ions. Stacks of sheets form what are called "books" because of their resemblance to pages.
What is the crystal structure of biotite?
Biotite–K(Mg,Fe)3AlSi3O10(OH)2–is a dark, iron-rich mica that has a monoclinic crystal system. The octahedral layer is entirely occupied by Mg2+ and Fe2+ and the mineral is therefore trioctahedral, since all octahedra are occupied.
What are the properties of biotite?
Properties of Biotite It is a black mica with perfect cleavage and a vitreous luster on the cleavage faces. When biotite is separated into thin sheets, the sheets are flexible but will break upon severe bending. When held up to the light, the sheets are transparent to translucent with a brown , gray, or greenish color.
What is the colour of biotite schist?
what is the Colour of biotite schist? black
What are the most common rock forming minerals?
Common rock-forming mafic minerals include olivine, pyroxene, amphibole, biotite mica, and the plagioclase feldspars. Felsic minerals are usually light in color and have specific gravities less than 3.0.
What is the formula for muscovite?
Muscovite (also known as common mica, isinglass, or potash mica) is a hydrated phyllosilicate mineral of aluminium and potassium with formula KAl2(AlSi3O10)(F,OH)2, or (KF)2(Al2O3)3(SiO2)6(H2O).
What is amphibolite used for?
It is used as paving stones and as a veneer or facing on buildings (both for interior and exterior use). It is also used as crushed stone for the usual crushed stone applications such as road and railroad bed construction. In this application it is used locally, near the source of the amphibolite.
Is plastic a mineral?
Plastic is not mineral. It is a solid and it has a definite chemical composition. However its atoms are not arranged in a regular way. Plastic is made from oil (an organic material) and it is made by humans - plastic is not a naturally occurring substance.
Is biotite a magnet?
Thus, biotite has both magnetic and structural two-dimensional aspects. We also have observed magnetic aftereffect, and some parasitic ferromagnetism below the transition.
What color is biotite?
In thin section, biotite exhibits moderate relief and a pale to deep greenish brown or brown color, with moderate to strong pleochroism. Biotite has a high birefringence which can be partially masked by its deep intrinsic color. Under cross-polarized light, biotite exhibits extinction approximately parallel to cleavage lines, and can have characteristic bird's eye maple extinction, a mottled appearance caused by the distortion of the mineral's flexible lamellae during grinding of the thin section. Basal sections of biotite in thin section are typically approximately hexagonal in shape and usually appear isotropic under cross-polarized light.
Where does biotite occur?
For instance, biotite occurs in the lava of Mount Vesuvius and in the Monzoni intrusive complex of the western Dolomites. Biotite in granite tends to be poorer in magnesium than the biotite found in its volcanic equivalent, rhyolite. Biotite is an essential phenocryst in some varieties of lamprophyre.
What is the name of the rock that is composed of mica?
An igneous rock composed almost entirely of dark mica (biotite or phlogopite) is known as a glimmerite or biotitite. Biotite may be found in association with its common alteration product chlorite. The largest documented single crystals of biotite were approximately 7 m 2 (75 sq ft) sheets found in Iveland, Norway.
What is biotite mica?
The term biotite is still used to describe unanalysed dark micas in the field. Biotite was named by J.F.L. Hausmann in 1847 in honor of the French physicist Jean-Baptiste Biot, who performed early research into the many optical properties of mica. Members of the biotite group are sheet silicates.
Why is biotite used in rock dating?
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 and magnesium between biotite and garnet is sensitive to temperature.
Why are biotite crystals called books?
When biotite crystals are found in large chunks, they are called "books" because they resemble books with pages of many sheets. The color of biotite is usually black and the mineral has a hardness of 2.5–3 on the Mohs scale of mineral hardness .
Is biotite an anisotropic substance?
Biotite dissolves in both acid and alkaline aqueous solutions, with the highest dissolution rates at low pH. However, bioti te dissolution is highly anisotropic with crystal edge surfaces ( h k 0) reacting 45 to 132 times faster than basal surfaces ( 001 ).
Biotite Image
Comments: Brown book of pseudohexagonal biotite crystals in matrix. Location: Sattleberg, Laacher See, Rhineland-Palatinate, Germany. Scale: Size Not Given. © Lou Perloff / Photo Atlas of Minerals
Calculated Properties of Biotite
Bulk Density (Electron Density)=3.07 gm/cc note: Specific Gravity of Biotite =3.10 gm/cc.
Other Biotite Information
See Also: Links to other databases for Biotite : 1 - Alkali-Nuts (English) 2 - Alkali-Nuts (Francais) 3 - Am. Min.
What are the features of biotite?
Striking Features. Flaky habit, crystals, sectility, and mode of occurence. Environment. Biotite is a common rock-forming mineral, and is especially noted in metamorphic rock s such as schist and gneiss. It is also found in igneous rock such as granite s and rhyolites.
How much does biotite weigh?
Biotite can come in enormous crystal sheets that can weigh several hundred pounds. Thin sheets can be peeled off as layers, and the thinner a layer is peeled the greater its transparency becomes. In 1998, the IMA removed the status of Biotite as an individual mineral species, and instead declared it as a group name for the following individual ...
Why is biotite called biotite?
Because of Biotite's abundance, its presence is usually lacking in collections except for it being an accessory mineral to other minerals. Biotite can come in enormous crystal sheets ...
Why is biotite hard to clean?
Biotite is very hard to clean because if washed it will absorb water internally and start to break apart.
Is biotite a conductor?
Biotite, like Muscovite, is a very poor conductor of heat and electricity, and is thus used as an insulator for various electrical products and semiconductors. Biotite is found in abundance worldwide, but collectors specimens are not common and come from few localities.
What is the chemical formula for biotite?
Biotite is the most common mica mineral and also known as black mica, a silicate mineral in the common mica group. Approximate chemical formula K (Mg, Fe). It can be found in massive crystal layers weighing several hundred pounds. It is abundant in metamorphic rocks (both regional and contact), pegmatites, ...
Where is biotite found?
Biotite is found in a wide variety of magmatic and metamorphic rocks. It is common in various magmatic and metamorphic rocks. In igneous rocks, more commonly in silicic and alkaline rocks, e.g. granites, diorite s, gabbros and peridotites.
Why is biotite used in metamorphic rocks?
Biotite is also useful for evaluating the temperature histories of metamorphic rocks, because the division of iron and magnesium between biotite and garnet is temperature sensitive.
What is biotite in shingers?
It is a fundamental component of many metamorphic shingers and form s in suitable compositions in a wide range of pressure and temperature. Biotite is estimated to be up to 7% of the exposed continental crust.
What is biotite used for?
The modified biotite, produced by hydrothermal or abrasion processes, produces vermiculite, a porous material used as an insulating material in gypsum wall panels and other heat insulation applications.
Why is biotite used in soil?
Biotite is commonly used to limit the age of rocks through potassium-argon escort or argon-argon escort.
What is similar to biotite?
Similar Species: Glauconite, commonly found in green pellets in sedimentary deposits, is similar in composition to biotite.
Why are biotite crystals called books?
When biotite crystals are found in large chunks, they are called "books" because they resemble books with pages of many sheets. The color of biotite is usually black and the mineral has a hardness of 2.5–3 on the Mohs scale of mineral hardness.
What is pyrite made of?
Pyrite is a brass-yellow mineral with a bright metallic luster. It has a chemical composition of iron sul fide (FeS2) and is the most common sulfide mineral. It forms at high and low temperatures and occurs, usually in small quantities, in igneous, metamorphic, and sedimentary rocks worldwide.
What elements make up hornblende?
Hornblende is an isomorphous mixture of three molecules; a calcium-iron-magnesium silicate, an aluminium-iron-magnesium silicate, and an iron-magnesium silicate. The general formula can be given as (Ca,Na)2–3 (Mg,Fe,Al)5 (Al,Si)8O22 (OH,F)2.
Where is muscovite formed?
Muscovite typically occurs in metamorphic rocks, particularly gneisses and schists, where it forms crystals and plates. It also occurs in granites, in fine-grained sediments, and in some highly siliceous rocks. Large crystals of muscovite are often found in veins and pegmatites.
What is the formula for muscovite?
Muscovite (also known as common mica, isinglass, or potash mica) is a hydrated phyllosilicate mineral of aluminium and potassium with formula KAl2(AlSi3O10) (F,OH)2, or (KF)2(Al2O3)3(SiO2)6(H2O).
Is Salt a mineral?
Salt is a mineral consisting primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in its natural form as a crystalline mineral is known as rock salt or halite. Salt is present in vast quantities in seawater, where it is the main mineral constituent.
What is biotite in rocks?
It has different roles in these rocks, though. It acts as the primary iron-bearing phase in many granitic rocks and as a hydrated potassium-bearing mineral in mafic rocks. Biotite is present in both silica under- and oversaturated rocks. Biotite, because it is the host of relatively uncommon chemical elements in a given magma, is a very common ingredient of pegmatites which crystallize from late-magmatic fluids. Large “books” are a common sight in pegmatitic rocks. Biotite in felsic rocks tends to be Fe-rich.
How does biotite form?
Biotite in the majority of cases forms when clay-rich sedimentary rocks are buried deep enough for the clay minerals to metamorphose to it. Biotite also forms in impure metamorphosed carbonate rocks and in metabasic rocks.
What are the end members of the biotite group?
End-members such as phlogopite, annite and siderophyllite all belong to the group. It is a common practice to distinguish between biotite and phlogopite like these two are mutually exclusive minerals with different compositions. This is no longer true.
Why is biotite abundant in intrusive rocks but usually resorbed in volcanic rocks?
The reason why biotite is abundant in intrusive but usually resorbed in volcanic rocks is that it is not a stable phase in magma at lower pressures. In metamorphic rocks too, biotite is present in a wide variety of rocks which formed under various temperature and pressure conditions.
Why is biotite less common in sedimentary rocks?
It is much less common in sediments and sedimentary rocks because it yields to clay minerals in the weathering environment. Biotite is one of the two most common members of the mica group. The other one is muscovite.
What are the metamorphic minerals that are found in pelitic rocks?
It remains the companion of several metamorphic minerals (muscovite, garnet, staurolite, Al-silicates, cordierite) that inhabit pelitic rocks at various depths in the crust. Biotite finally disappears at the granulite facies conditions where hydrous minerals (which it is) are not stable. Metapelitic rocks that contain lots of biotite are various schists (biotite schist, biotite-chlorite schist, albite-biotite schist, garnet-mica schist).
What is the characteristic of mica?
That gives rise to the most characteristic feature of micas: perfect basal cleavage. As a result of that, biotite readily cleaves into parallel and flexible sheets. This property together with the softness (2.5-3 on the Mohs scale) and good reflectance makes it one of the most easily identifiable common minerals.
