Magnesite Mg2CO3 Hexagonal

Description: Magnesite is found in highly magnesium-rich rocks, usually of a metamorphic origin. These included metamorphosed marbles and ultramafic rocks. It is usually associated with other magnesium-rich minerals such as talc and serpentine.

MARINETTE COUNTY: Magnesite is a major component of a light gray massive, medium-grained rock outcropping in the SW NE and SE NW of sec. 21 T.37N. R.21E. near Pembine, where it occurs intergrown with serpentine, quartz and talc. Accessory minerals include chromite, pyrite and serpentine. The magnesite is in equigranular grains up to 5 mm. across. The deposit was prospected in the 1940's as an economic source of magnesium. ( WGNHS files, 1945; U.S.G.S., 1976.)

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