biotite and muscovite Flashcards
A generally black or dark green form of mica that is a constituent of crystalline rocks and consists of a silicate of iron, magnesium, potassium, and aluminum.
Biotite
Abundant in metamorphic rocks (both regional and contact), in pegmatites, and also in granites and other intrusive igneous rocks.
Biotite
Also known as black mica.
Biotite
Color of biotite
Brown to black (sometimes greenish)
Specific Gravity of biotite
2.7-3.4
Hardness of biotite
2.5-3
Chemical formula of biotite
K(Mg,Fe)3 AISI3 O10(F,OH) 2
Streak of biotite
White or gray
Class of biotite
Silicates
Transparency of biotite
Transparent or translucent
Cleavage of biotite
Perfect Cleavage
Biotite was named in honor to ______________, a French physicist, mathematician, and astronomer who researched the mica minerals for their optical properties.
Jean Baptiste Biot (1774-1862)
Luster of biotite
Pearly luster
Biotite is commonly used to limit the age of rocks through _____________ or _____________.
potassium-argon escort or argon -argon escort
useful for evaluating the temperature histories of metamorphic rocks because the division of iron and magnesium between this and garnet is temperature
sensitive
biotite
This is a common mineral that belongs to
the mica group.
Muscovite
The name Muscovite derives from its use in window as ____________.
Muscovy glass
In the _______ muscovite was mined for this use from pegmatites in the area around ___________.
1700s, Moscow, Russia
Color of muscovite
can be colorless, white, or pale shades of pink, brown, green, or yellow
Specific gravity of muscovite
2.8 to 2.9
Hardness of muscovite
2.5-3
Chemical formula of muscovite
KAl2(Si3AlO10)(OH)2
Streak of muscovite
White, often sheds tiny flakes
Class of muscovite
Silicates
Transparency of muscovite
Transparent or translucent
Cleavage of muscovite
Perfect Cleavage
Luster of muscovite
Pearly to vitreous
Formed in metamorphic, igneous, and sedimentary environments. It is a common mineral in metamorphic rocks, especially in schist and gneiss.
Muscovite
This can also be found in igneous rocks such as granite, pegmatite, and
syenite. In these rocks, it typically forms as a result of hydrothermal alteration, which occurs when hot fluids circulate through the rock and alter the mineral composition.
Muscovite
Muscovite is sometimes cut and polished into _________ and used in jewelry.
cabochons
Muscovite has a number of industrial uses:
- filler in the production of rubber and plastics
- insulating material in the electrical industry
- component in building materials such as drywall and cement
Muscovite is also used in the production of ___________, ___________, and ___________.
lubricants, cosmetics, and paints
In addition to its industrial uses, muscovite is also used as a __________ and as a __________.
decorative stone, gemstone
