Garnet

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Garnet
GarnetCrystalUSGOV.jpg
General
Category Nesosilicate
Chemical formula The general formula X3Y2(SiO4)3
Identification
Color virtually all colors, blue very rare
Crystal habit Rhombic dodecahedron or cubic
Cleavage Indistinct
Fracture conchoidal to uneven
Mohs Scale hardness 6.5–7.5
Luster vitreous to resinous
Polish luster vitreous to subadamantine[1]
Refractive index 1.72–1.94
Optical Properties Single refractive, often anomalous double refractive[1]
Birefringence
Ultraviolet fluorescence
Streak White
Specific gravity 3.1–4.3
Other Characteristics variable magnetic attraction
Major varieties
Pyrope Mg3Al2Si3O12
Almandine Fe3Al2Si3O12
Spessartine Mn3Al2Si3O12
Andradite Ca3Fe2Si3O12
Grossular Ca3Al2Si3O12
Uvarovite Ca3Cr2Si3O12

A garnet /ˈɡɑrnət/ is one kind of silicate mineral. There are many different kinds of garnets, containing different metals. Crystals of garnet are often large and pretty. Their most common color is red or purple, but they can be found in almost all colors and are often used in jewelry. In the United States, garnet is the birthstone for people born in the month of January.

Related pages[change | change source]

Sources[change | change source]

  1. 1.0 1.1 Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6

Further reading[change | change source]

Other websites[change | change source]