Garnet

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Garnet
GarnetCrystalUSGOV.jpg
General
CategoryNesosilicate
Formula
(repeating unit)
The general formula X3Y2(SiO4)3
Identification
Colorvirtually all colors, blue very rare
Crystal habitRhombic dodecahedron or cubic
CleavageIndistinct
Fractureconchoidal to uneven
Mohs scale hardness6.5–7.5
Lustervitreous to resinous
StreakWhite
Specific gravity3.1–4.3
Polish lustervitreous to subadamantine[1]
Optical propertiesSingle refractive, often anomalous double refractive[1]
Refractive index1.72–1.94
BirefringenceNone
PleochroismNone
Ultraviolet fluorescencevariable
Other characteristicsvariable magnetic attraction
Major varieties
PyropeMg3Al2Si3O12
AlmandineFe3Al2Si3O12
SpessartineMn3Al2Si3O12
AndraditeCa3Fe2Si3O12
GrossularCa3Al2Si3O12
UvaroviteCa3Cr2Si3O12

A garnet /ˈɡɑːrnət/ 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]