Spinel
Amity, Orange County
New York

This specimen measures 18cm x 12cm


Spinel     MgAl2O4

Oxides; magnesium aluminum oxide, in which magnesium can be partly or completely replaced by iron, zinc, or manganese

Color and Luster: Red, green, blue, brown, black; vitreous, dull; streak white

Hardness: 7.5-8

Cleavage: None

Fracture: Conchoidal, brittle

Crystals: Isometeric; usually octahedrons; cubes and dodecahedrons rare; also granular, compact, disseminate

Photo by Mary Sutherland


Descriptions taken from
The Audubon Society Field Guide to North American Rocks and Minerals