Magnesite

- align=center bgcolor="#9966FF"	Magnesite		- align=center	- align=center bgcolor="#9966FF"	General		-	Category	Mineral	-	Chemical formula	magnesium carbonate:MgCO₃	- align="center" bgcolor="#9966FF"	Identification		-	Color	White	-	Crystal habit	usually massive, rarely as rhombohedrons or hexagonal prisms	-	Crystal system	trigonal; bar 3 2/m	-	Cleavage	Perfect, ^* Perfect	-	Fracture	Brittle - Conchoidal	-	Mohs Scale hardness	3.5 - 5	-	Luster	Vitreous	-	Refractive index	Uniaxial (-) nω=1.508 - 1.510 nε=1.700	-	Pleochroism	N/A	-	Streak	white	-	Specific gravity	3.0 - 3.2	-	Fusibility	infusible	-	Solubility	Effervesces in hot HCl	-	Other Characteristics		- align="center" bgcolor="#9966FF"

Magnesite is magnesium carbonate, MgCO₃. Iron (as Fe²⁺) substitutes for Mg with a complete solution series with siderite, FeCO₃. Calcium, manganese, cobalt, and nickel may also occur in small amounts. Dolomite, (Mg,Ca)CO₃, is almost indistinguishable from magnesite.

Magnesite occurs as veins in and an alteration product of serpentine and other magnesium rich rock types in both contact and regional metamorphic terranes. These magnesites often are cryptocrystalline and contain silica as opal or chert.

Uses

Magnesite can be used as a slag former in steelmaking furnaces, in conjunction with lime, in order to protect the magnesium oxide lining. It can also be used as a catalyst and filler in the production of synthetic rubber and in the preparation of magnesium chemicals and fertilizers.

References and external links

Dana's Manual of Mineralogy ISBN 0471032883
Smithsonian Rock and Gem ISBN 0-7566-0962-3
Mineral Galleries
Webmineral.com
Mindat.org
Minerals.net

Magnesium minerals | Carbonate minerals

Gourt Home::Gourt :: Magnesite

Uses

References and external links