Magnesite | |
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![]() Magnesite crystals from Brazil (11.4 × 9.2 × 3.6 cm) | |
General | |
Category | Carbonate mineral |
Formula (repeating unit) | MgCO3 |
IMA symbol | Mgs[1] |
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 | [2][3][4][5] |
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.