The word Mica is derived from the Latin word “micare”, which means “to shine”, in reference to its glittering effect when exposed to light. Mica is a non-metallic mineral that exhibits perfect basal cleavage. The mica group represents a total of 37 different types of mica. Muscovite and Phlogopite are important micas for commercial application. Muscovite is by far the most frequently mined and used type of mica. A typical chemical composition of Muscovite Mica is silica (SiO2) – 45%; alumina (Al2O3) – 38%; potassium oxide (K2O) – 12%; other – 5%.
Mica’s reflective optical properties are utilized in cosmetics as well as in paints & coatings. Besides it’s glittering and aesthetic effects, mica is used in a wide range of industrial applications. The construction and plastic industries use mica as a functional filler. Given its diverse properties and applications, mica is found in a significant number of parts and materials used in the automotive industry. Mica can withstand high temperature which makes it a useful component for welding and frictional systems. Mica is used as a lubricant in the oil & gas drilling sector.
| MICA TYPE | Composition formula | Characteristics |
|---|---|---|
| Muscovite | KAl2(AlSi3)O10(OH)2 | Rude ore is a brownish natural platy mineral. Octahedral ions in a crystal are mostly occupied with Al. |
| Phlogopite | KMg3(AlSi3)O10(OH)2 | Phologopite is darker than muscovite and soft. Octahedral ions in a crystal is mostly occupied with Mg. |
| Sericite | KAl2(AlSi3)O10(OH)2 | Rude ore is a greenish gray, natural platy mineral, same composition as muscovite but its smaller crystals due to hydrometamorphism |
| Synthetic Fluoro Phlogopite | KMg3(AlSi3)O10F2 | Synthetic fluorophlogopite, contains no (OH) of the natural phlogopite instead the (OH)- is fully substituted with F. White and a little rigid. |
| Physical property | Unit | Value referring to literature etc. |
|---|---|---|
| True specific gravity | kg/m3 | (2.6～3.2)×103 |
| Mohs hardness | - | 2.0～3.2 |
| Specific heat | J/kg・K | 860～870 |
| Thermal conductivity (in direction perpendicular to a cleavage surface) | J/m・s・K | 0.67 |
| Dehydrating temperature of OH in crystal | ℃ | 550 |
| Melting point | ℃ | 1,250 |
| Ignition loss (900℃-3hr) | wt% | 4～5 |
| Tensile strength | Pa | (25～30)×107 |
| Dielectric breakdown voltage | kV/0.1mm | 18～25 |
| Relative permittivity (50Hz) | - | 6.5～9 |
| Dielectric loss tangent (50Hz, 25℃) | % | 0.01～0.02 |
| Volume resistivity | Ω・m | 1010～1013 |
| Coefficient of liner expansion | m/m・K | 3.6×10-5 |
| Refractive index | - | nα=1.552～1.576 nβ=1.582～1.615 nγ=1.587～1.618 |