Mineralpedia Details for Margarite

Phyllosilicate - Monoclinic - Mica group member. Brittle - Dioctahedral. Al occupying the (M) octahedral positions with sub's of Lithium, Ca (or possibly Na) at the Interlayer spots, and hydroxyl at the (A) positions. Be and Al can replace Si at the (T) positions. For more information on Mica minerals and other phyllosilicates please reference our article - Click Here.

Rarely as good pseudohex. crystals, usually scaly or platy aggregates. Grayish pink to pink, but also yellowish. Occurs mainly with diaspore in contact metamorphic deposits (Bernard & Hrysl), also in chlorite schists (Mindat). Associated with corundum, diaspore, tourmaline, staurolite, glauphane, chlorite, and magnetite...in high aluminun deposits (Handbook of Min.).

Formula

CaAl₂(Si₂Al₂)O₁₀(OH)₂ 

Crystal System

Monoclinic 

Crystal Habit

Lamellar, Massive - Lamellar, Scaly 

Cleavage

Good, None, None 

Luster

Pearly 

Color

white, gray, pinkish gray, yellowish gray 

Streak

white 

Class

Monoclinic - Prismatic 

Fracture

Brittle 

Hardness

4 

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Mindat

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Phyllosilicate - Monoclinic - Mica group member. Brittle - Dioctahedral. Al occupying the (M) octahedral positions with sub's of Lithium, Ca (or possibly Na) at the Interlayer spots, and hydroxyl at the (A) positions. Be and Al can replace Si at the (T) positions. For more information on Mica minerals and other phyllosilicates please reference our article - Click Here.

Rarely as good pseudohex. crystals, usually scaly or platy aggregates. Grayish pink to pink, but also yellowish. Occurs mainly with diaspore in contact metamorphic deposits (Bernard & Hrysl), also in chlorite schists (Mindat). Associated with corundum, diaspore, tourmaline, staurolite, glauphane, chlorite, and magnetite...in high aluminun deposits (Handbook of Min.).