Garnet as gemstones. The gemstone varieties occur in shades of green, red, yellow, and orange. In the US it is known as the birthstone for January. It is the state mineral of Connecticut, New York's gemstone, and star garnet (garnet with rutile asterisms) is the state gemstone of Idaho. Garnet sand is a good abrasive, and a common replacement for silica sand in sand blasting. Alluvial garnet grains which are rounder are more suitable for such blasting treatments. Mixed with very high pressure water, garnet is used to cut steel and other materials in water jets. For water jet cutting, garnet
Garnet been called "hessonite" from the Greek meaning inferior. Grossular is found in contact metamorphosed limestones with vesuvianite, diopside, wollastonite and wernerite. Grossular garnet from Kenya and Tanzania has been called tsavorite. Tsavorite was first described in the 1960s in the area of Kenya, from which the gem takes its name. Uvarovite is a calcium chromium garnet with the formula CaCr(SiO). This is a rather rare garnet, bright green in color, usually found as small crystals associated with chromite in peridotite, serpentinite, and kimberlites. It is found in crystalline marbles and schists in the Ural mountains of Russia and Outokumpu, Finland.