Cochise College          Photos of Minerals

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                          Roger Weller, geology instructor

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                                  copyright 2007-R.Weller
 

Mineral Information on:
garnet

Chemical Group:    silicate

Chemical Formula:     Garnet is R₃''R₂'''(SiO₄)₃  (general formula)
Almandite is Fe₃Al₂(SiO₄)₃       Pyrope is Mg₃Al₂(SiO₄)₃
Spessartite is Mn₃Al₂(SiO₄)₃      Grossulariteis Ca₃Al₂(SiO₄)₃
Andradite is Ca₃Fe₂(SiO₄)₃        Uvarovite is Ca₃Cr₂(SiO₄)₃

Color: red, dark red, reddish brown, brown, green, gray, pink    

Streak:  white or lighter shade of solid color

Hardness:  7 to 7.5         Specific Gravity:  3.6 to 4.3                Fracture:

Cleavage:   none
 

Crystal Forms: Isometric system
     Crystals are usually dodecahedrons or trapezohedrons or modifications of these two shapes.

Mineral Associations:  Garnets are found in metamorphic rocks.

Identifying Characteristics:  color and crystal shape

Uses:  gemstones and abrasives

Occurrences: Czechoslovakia; in the USA Gore Mountain in New York 

Toxicity:      when-swallowed- low           when inhaled- high

Additional Information:  The ancient name for garnet was carbuncle.