Mica, which is essentially a compound of silicate minerals, is comprised of closely related materials that have perfect basal cleavage. They are monoclinic with a tendency of pseudohexagonal crystals, having similar chemical composition. They belong to the category of principal rock-forming minerals and are found in various categories like sedimentary, igneous, and metamorphic.

How is Mica Formed?
Micas do originate as a result of diverse processes and several conditions. There are various processes of formation that includes deposition by fluids derived from magmatic activities, consolidating magmas, deposition of fluid circulating by both contact and regional metamorphism, and also by alternate process. They are even caused by weathering of feldspar and minerals. The presence of mica or chemical composition can serve as geothermometers or geobarometers.
Distinct crystals of micas occur in few rocks, like igneous and pegmatites. Micas may occur in large crystals or books, and they measure up to several meters across. The mica grains are extremely small and have characteristic shiny cleavage surfaces. Glauconite, an iron potassium phyllosilicate of what is mica group formed in marine environments, is also found in seafloors where clastic sedimentation occurs. Although the glauconite is interpreted to be formed from pre-existing layered silicates, most of it appears to be crystallized from the aluminosilicate gels, which is influenced by biochemical activities that reduce the environment. The common rock-forming micas are distributed widely. Biotite occurs in igneous rocks, pegmatite occurs in masses. During chemical weathering, it’s usually rare in the sedimentary rocks and sediments. Also, biotite tends to lose its elasticity and become decolorized due to the appearance of greyish silver flakes.

Weathered biotite is golden yellowish, having a bronzy luster and having the appearance of gold flakes. Muscovite is another hydrated phyllosilicate mineral that commonly occurs in metamorphic gneisses and phyllites. Muscovite occurs as microscopic grains and gives the rock a silky luster. Much of the muscovite in igneous rocks is thought of being having formed late. It’s relatively resistant to weathering and occurs in soils, clastic sediments and sedimentary rocks are derived from them. Phlogopite is rare in igneous rocks, but it contains some ultramafic rocks. It occurs in periodontitis, kimberlites where rocks in diamond occur. They are a unique constituent of some magnesium-rich pegmatites. It’s generally found in impure limestone that has undergone contact metasomatism, a procedure through which the chemical composition of the rocks is changed.

What is Mica Used For?
Mica is a naturally occurring stone directly applying to a set of minerals having silica in its highest form. Mica finds various usages in different industries. Let’s find out some of them.

Various Properties of Mica
Mica belongs to a very important and large group of minerals that are highly suitable for various applications. Mica has some properties distinguished from others.
1.Physical Properties: Mica is translucent and can be easily split into thin films along its cleavage. Its optically flat, colorless, firm like thin sheets, elastic, and of course, incompressible.
2.Chemical Properties: It is a compound of hydrous silicate of aluminum, containing iron, potassium, magnesium, sodium fluorine, and also a few traces of numerous other elements. It is static to the action of water, and even acids barring a few like hydrofluoric and concentrated sulfur. It remains unchanged by atmospheric effects.
3.Electrical Properties: Mica has the exclusive combination of uniform dielectric steadiness, capacitance stability, and enormous dielectric power. It has a high Q factor and lower power loss, low-temperature coefficient, and high electrical resistance. It has a high resistance to arc, corona discharge without causing any lasting injury effect.
4.Thermal Properties: Mica is highly fireproof, non-flammable, incombustible, infusible, and can resist temperature up to 1000 degrees Celsius. Although the thermal properties largely depend on a lot on the type and variety of what is mica used, it has excellent thermal stability. Mica is characterized by low heat conductivity and can be easily exposed to high temperatures without any visible effect.
5.Mechanical Properties: Mica is highly tough and has high tensile strength. It’s elastic and also flexible. Mica possesses immense compression power and can be machined, hand-cut or die punched.