Uvarovite Garnet: Gemstone Information
Uvarovite Garnet is found in association with chromite, serpentinites, ultramafic rocks and other chromium-bearing rocks; also in skarns. Notable occurrences are in the Ural mountains, particularly at the original locality of Sarany near Bisersk and in the vicinity of Kyshtymsk, north-east of Zlatoust. The largest crystals occur at Outukumpu, Finland.
Uvarovite also occurs in Val Malenco, Lombardy, Italy; and in the Kop Krom mine, Erzerum, Turkey. In Canada, it was found in Quebec at Magog, Stanstead Co., Thetford, Megantic Co., and Wakefield. In the US, it occurs in California near Livermore, Alameda Co., and in Jackson, Amador Co.
Properties
Within the ugrandite series whilst there is extensive solid solution between uvarovite and grossular only limited solid solution exists between uvarovite and andradite. Limited solid solution also exists between uvarovite, pyrope and knorringite and the hydrogarnets. Consequently the physical and chemical properties and appearance can
vary appreciably. Because of the solid solution between uvarovite and grossular many green garnets are mistakenly termed ‘uvarovites’ when they are really chromian grossular, particularly when they are from
established uvarovite localities such as Sarany.
Refractive Index
The calculated value for the end-member is 1.865 but with isomorphous replacement, particularly by grossular, this can fall to 1.798
for =Uv50.
Density
The calculated value for the end-member is 3.848 but with isomorphous replacement, particularly by grossular, this can fall to 3.712 for =Uv50.
Colour
Uvarovite has an intense green color and fine pieces feature a sparkling, bright-green surface of small crystals that cover the rock matrix thickly, evenly and smoothly. Large crystals are significantly darker.
Use
Uvarovite is seldom found in gem crystals of cuttable size and consequently gems are both rare and tiny. Because the overall appearance of matrix specimens is so striking, thin-shaped pieces for setting in jewellery are produced where much of the supporting matrix is cut away leaving an uninterrupted thick-pile, medium-grain, bright-green vitreous drusy crystal covering from edge to edge.