Magnesite
| Magnesite | |
|---|---|
Magnesite crystals from Brazil (11.4 × 9.2 × 3.6 cm) | |
| General | |
| Category | Carbonate mineral |
| Formula | MgCO3 |
| IMA symbol | Mgs |
| Strunz classification | 5.AB.05 |
| Crystal system | Trigonal |
| Crystal class | Hexagonal scalenohedral (3m) H-M symbol: (3 2/m) |
| Space group | R3c |
| Identification | |
| Color | Colorless, white, pale yellow, pale brown, faintly pink, lilac-rose |
| Crystal habit | Usually massive, rarely as rhombohedrons or hexagonal prisms |
| Cleavage | [1011] perfect |
| Fracture | Conchoidal |
| Tenacity | Brittle |
| Mohs scale hardness | 3.5–4.5 |
| Luster | Vitreous |
| Streak | white |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 3.0–3.2 |
| Optical properties | Uniaxial (−) |
| Refractive index | nω=1.508 – 1.510 nε=1.700 |
| Birefringence | 0.191 |
| Fusibility | infusible |
| Solubility | Effervesces in hot HCl |
| Other characteristics | May exhibit pale green to pale blue fluorescence and phosphorescence under UV; triboluminescent |
| References | |
Magnesite is a mineral with the chemical formula MgCO
3 (magnesium carbonate). Iron, manganese, cobalt, and nickel may occur as admixtures, but only in small amounts.