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. Magnesite occurs naturally in both cryptocrystalline and crystalline forms depending on the conditions of formation.
Magnesite is used in the production of magnesium oxide for the refractory lining of kilns and furnaces, as well as artistically in jewelry and sculpture. Since it may be formed by carbonation of magnesium serpentine, there have also been efforts to use magnesite for carbon sequestration.