Cochise College          Photos of Minerals

                          Geology Home Page                

                          Roger Weller, geology instructor

                                  copyright 2007-R.Weller


Mineral Information on:

Chemical Group:  sulfide

Chemical Formula: 

Color:  flint gray to iron black                Streak:  gray to black, sometimes with brownish tint

Transparency:  opaque, sometimes translucent cherry red               Luster:  metallic, splendent


Hardness:  3 to 4         Specific Gravity:   4.4 to 5.1           Fracture: subconchoidal to uneven

Cleavage:  none           Tenacity:  brittle


Crystal Forms:  Isometric system-tetrahedral
             Mineral obtained its name by crystallizing commonly in tetrahedrons or modified tetrahedrons.

Mineral Associations:  chalcopyrite, bornite, pyrite, sphalerite, galena, argentite

Identifying Characteristics:  Tetrahedron crystal shapes and dark color

Uses: ore of antimony and copper; may also contain silver

Occurrences:  Romania, Czechoslovakia, Austria, Bolivia;
     In the USA in Colorado, Utah, and Nevada

Toxicity:      when-swallowed- poisonous         when inhaled-poisonous   (may also include arsenic)

Additional Information:  Tetrahedrite is also known as gray copper ore.