UVAROVITE

Description:

Uvarovite is a variety of garnet, namely, green Calcium Chromium garnets, and is named after Russian Count Sergey Semeonovich Uvarov (1786-1855), Russian statesman and scholar, president of the Academy of St Petersburg (1818-1855). It was discovered in 1832 and its type locality is in Permskaja region, Ural Mountains, Russia.

There are six species of common garnets based on ideal end-member chemical compositions. The garnets are a group of mineral species all having essentially the same isometric crystal structure but varying in chemical composition and in many of their physical properties. Perhaps the most reliable method outside of chemical analysis for determining garnet species and varieties in gem garnets is by comparing their absorption spectrum, refractive index and color, which gives a conclusive identification.

Uvarovite is a member of calcium garnet group and is the rarest of all the garnets. It is also the only consistently green garnet, with a beautiful emerald-green color. It occurs as well-formed fine sized crystals and is rather brittle. Specimens of uvarovite are much sought after by collectors for outstanding brilliance and color. The best indicators of uvarovite are crystal habit, color, locality and hardness.

Uvarovite, like other garnets, forms rounded crystals with 12 rhombic or 24 trapezoidal faces or combinations of these and some other forms. This crystal habit is classic for the garnet minerals. As with the other calcium garnets (andradite and grossular), uvarovite is formed from the metamorphism of impure siliceous limestones and some other rocks that contain chromium.

All varieties of garnets have been used as gemstones for many thousands of years. Historically, garnets were believed to give protection from wounds and poison, to stop bleeding and to symbolize truth & fidelity, and bring prosperity. As gemstones, garnets today are more popular than ever. Some of the newer varieties have only become available in recent years. Garnets are also used today for a number of abrasive purposes.

Characteristics:

Chemistry: Ca3Cr2(SiO4)3, Calcium Chromium Silicate

Class: Silicates

Hardness (Mohs scale): 6.5 – 7.5

Density: 3.40 - 3.80

Refractive index: 1.74 – 1.87

Dispersion: 0.022 – 0. 057

Crystal System: Isometric

Crystal habit: typical rhombic dodecahedron

Fracture: conchoidal

Cleavage: None 

Transparency: transparent to translucent

Lustre: vitreous, glassy