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The Gemstone Grossular (Garnet)

Brownish Hessonite Grossular Garnet

Grossular is the most varicolored of the Garnets. The term Garnet describes a group name for several closely related minerals that form important gemstones, and Grossular is an individual member mineral of the Garnet group. Pure Grossular is colorless; the wide range of colors in this Garnet is caused by various impurities. Some Grossular types have their own unique variety or trade names, and are only called by these names in the gemstone market. The orange-brown Hessonite and deep green Tsavorite varieties are the best known varieties. In the gem trade, the term Grossularite is synonymous with Grossular, and both names are acceptable names for describing this gemstone.

Color

? White, Colorless, Red, Green, Yellow, Orange, Brown, Pink, Purple, Gray

Hardness

? 6.5 - 7.5

Chemical Formula

? Ca3Al2Si3O12

Mineral Class

? Grossular (Garnet)

Additional Properties

Crystal System
? Isometric
Refractive Index
? 1.738 - 1.745
Double Refraction
? None
Transparency
? Transparent
SG
? 3.6
Luster
? Vitreous to adamantine
Cleavage ? None

All About

Of the Grossular Garnets, Hessonite and the yellow to yellow-green form are the varieties most often used as gemstones. The rare green Tsavorite is the most valuable Grossular variety, if not the most valuable Garnet type in general. Tsavorite is a relatively recent gemstone type, and having been marketed well, created a new gemstone sensation and very good substitute for Emerald. The other forms of Garnet, such as the raspberry-red variety from Mexico and rare colorless type, are seldom used as gemstones. In the gem trade, the term Grossular or Grossularite on its own usually describes only the yellowish to yellowish green form of Grossular.

Uses

? Grossular Garnet can be cut into various gems, although it is not used as extensively as the other Garnet forms. It is not commonly seen in jewelry, though Hessonite and the yellow-green to yellow variety are increasing in popularity. For additional information on the uses of Tsavorite, see the Tsavorite gemstone page.

A compact, massive form called Hydrogrossular is sometimes used as carving gemstone and polished in cabochons. Hydrogrossular is usually greenish, but can also be pink and multicolored.

Varieties

?

Treatments & Enhancements

? Grossular gemstones are not enhanced, and their colors are always natural.

The Gemstone Grossular (Garnet) Sources

? Sources of Grossular Garnet include Kenya, Tanzania, Mali, Italy, Russia, Mexico, Canada (Quebec), and the U.S. (Maine, Vermont, and California).

Similar Gemstones

? There are many gemstones that can resemble Grossular gemstones. Topaz and Citrine can be very similar to Hessonite, and yellow Topaz, Heliodor, and Peridot can look similar to yellow to yellowish-green Grossular. Emerald and green Tourmaline can have the same color as the Tsavorite variety.

The Gemstone Grossular (Garnet) Photos

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See the variety Tsavorite for additional images.

The Gemstone Grossular (Garnet) in the Rough Photos

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See the variety Tsavorite for additional images.

The Gemstone Grossular (Garnet) Jewelry Photos

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