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 clean material. The common problems with this material are the presence of ilmenite and chloride compounds. Since the material has been naturally crushed and ground on the beaches for past centuries, the material is normally available in fine sizes only. Most of the garnet at the Tuticorin beach in south India is 80 mesh, and ranges from 56 mesh to 100 mesh size. "River garnet" is particularly abundant in Australia. The river sand garnet occurs as a placer deposit. "Rock garnet" is perhaps the garnet type used for the longest period of time. This type of garnet is produced in