MICA

Physical properties

Habit: micaceous, scaly, lamellar.
Color: brown, gray, green, yellow, or reddish brown.
Streak: white.
Diaphaneity: transparent to translucent.
Luster: vitreous, pearly.
Cleavage: (001) perfect.
Fracture: uneven.
Twinning: [310].
Dielectric properties.
Relative permittivity: 6.5 to 8.7, dielectric field strength: 50–150 kV/mm, loss tangent 0.004 to 0.070, electrical resistivity 10¹² to 10¹⁵ ohm.m.
Occurrence: contact and regional metamorphic limestones and dolomites.

Agricultural Uses

Phlogopite is one of the most commonly present micas and is denoted as K(Mg,Fe)₃AlSi₃O₁₀(OH,F)₂.Mica is commonly found as small flakes or lamellar plates without a crystal outline. Thin cleavage sheets of mica, particularly muscovite and phlogopite, are elastic, flexible and tough. They range from translucent to transparent. They have low electrical and thermal conductivity and high dielectric strength, and hence are used as electrical insulators.