Group: Ferromagnesin("dark")Silicate

Mineral: Olivine

Chemical Composition: (Mg,Fe)2SiO4

Common Characteristics: Green to brown color; glassy luster; gemperidot

Mineral: Pyroxene group

Chemical Composition: (Mg,Fe)SiO3

Common Characteristics: Green to black color, commonly has two cleavage planes at 90 degrees.

Mineral: Amphibole group (Hornblende)

Chemical Composition: (CA2(Fe, Mg)5Si8O22(OH)2

Common Characteristics: Black or dark green color; often appear as elongated rod-shaped crystals

Mineral: Biotite mica

Chemical Composition: K(Mg,Fe)3AlSi3O10(OH)2

Common Characteristics: Black or brown; often appear as hexagonal crystals in thin sheets.

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