Microlite
Microlite is a very rare member of the Pyrochlore group of minerals. As a mineral, it is usually opaque to translucent and plentiful in some locations. Gem quality crystals, however, are quite rare and very small so faceted gems tend to be small and are extremely rare. Microlite is a beautiful gem that is found in colors of pale to bright yellow, brown, reddish and green. Current sources of gem grade Microlite are the Alto do Giz pegmatite, and Virgem da Lapa, Minas Gerais, Brazil.
| Category: | Pyrochlore Supergroup |
| Crystallography: | Isometric – Hexoctahedral |
| Crystal Habit: | Commonly as euhedral to subhedral octahedra, modified by the dodecahedron, cube, to 8 cm; also granular, massive. Twinning: Rare, according to the spinel law, twin plane. |
| Cleavage: | [111] Poor |
| Fracture: | Irregular, Uneven, Splintery, Sub-Conchoidal |
| Tenacity: | Brittle |
| Moh’s Hardness: | 5.0 – 5.5 |
| Density: | 4.20 – 6.4 (g/cm3) |
| Radioactivity: | Not Radioactive |
| Color: | Yellow, Pale yellow to reddish brown, sometimes emerald-green |
| Transparency: | Opaque to Translucent, Transparent in thin fragments |
| Luster: | Vitreous to Adamantine, Resinous on fractures |
| Refractive Index: | 1.93 – 2.02 Isotropic |
| Birefringence: | 0.00 (Isotropic) |
| Dispersion: | n/a |
| Pleochroism: | None |
