Magnesite
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameMagnesite
Chemical FormulaMgCO₃
Mohs Hardness3.5
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavageperfect rhombohedral {1011}
Fractureconchoidal
Specific Gravity3
Colorswhite, cream, light brown
Transparencytranslucent
Type LocalityFreiberg District, Erzgebirge, Saxony, Germany
Mineral GroupCarbonates
Usesrefractory material, source of magnesium, chemical industry, collector
Associated Mineralsserpentine, talc, dolomite, calcite
Raritycommon
Description
This specimen features a crust of numerous small, botryoidal to granular magnesite crystals, predominantly white to off-white with some areas exhibiting a light brownish hue, covering a matrix.
Geological Context
Magnesite commonly forms as an alteration product of magnesium-rich rocks such as serpentinite and peridotite, or in sedimentary environments through the replacement of dolomite or direct precipitation from magnesium-rich brines.
