Geology Home Page
Roger Weller, geology instructor
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
Specific Gravity: 3.6 to 4.3
Crystal Forms: Isometric
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.