Uvarovite

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Uvarovite
Uvarovite-tuc09103c.jpg
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 [1][2][3]

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.[1]

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)

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