Uvarovite

Uvarovite
240px Uvarovite druse from Urals Region, Russia (size: 18.3 x 13.1 x 2.0 cm)
General
Category	Nesosilicate
Formula (repeating unit)	Ca3Cr2Si3O12
Strunz classification	09.AD.25
Crystal symmetry	Isometric hexoctahedral H-M symbol (4/m32/m) Space group: I a3d
Unit cell	a = 11.99 Å; Z=8
Identification
Color	Green, emerald-green, green-black
Crystal habit	Euhedral crystals, granular, massive
Crystal system	Cubic
Fracture	Uneven, conchoidal
Mohs scale hardness	6.5-7.5
Luster	Vitreous
Streak	White
Diaphaneity	Transparent, translucent
Specific gravity	3.77 - 3.81
Optical properties	Isotropic
Refractive index	n = 1.865
Other characteristics	Fluorescent red in both short and long UV
References

Uvarovite is a chromium-bearing garnet group species with the formula: Ca₃Cr₂(SiO₄)₃. It was discovered in 1832 by Germain Henri Hess who named it after Count Sergei Semenovitch Uvarov (1765–1855), a Russian statesman and amateur mineral collector.

Uvarovite is one of the rarest of the garnet group minerals, and is the only consistently green garnet species, with an emerald-green color. It occurs as well-formed fine-sized crystals.

It is found associated with chromium ores in Spain, Russia, and Quebec in Canada. It also occurs in Finland, Norway, and South Africa.

Pendant in uvarovite, a rare bright-green garnet. The long dimension is 2 cm (0.8 inch)

See also

• List of minerals named after people