What Is Garnet Schist?

Features

• Garnet schist is a silica mineral, and it will crystallize equally in all directions. It does not have cleavage and when pressure is applied, it will break into sharp, irregular pieces. Garnet schist is very hard, ranging between 6.5 and 7 on the Mohs hardness scale. It may be gray, silvery gray or brown in color with a sparkling look due to layers of mica and embedded garnet crystals.

Geography

• In the United States, garnet schist can be found in Idaho, New York and Montana. Many other nations mine garnet schist, including China, India, Russia, Australia and Turkey.

Function

• Garnet schist is often used in industry settings. It is ground down and then used as an abrasive. While it was originally used to make sanding belts and sanding discs, today it is often used to make abrasive powders and as an abrasive blasting material. It is also used in water filtration and the water used for water jet cutting.

Alternatives

• There are several other abrasive materials that could be used instead of garnet schist. Natural minerals that could be used instead include quartz, diamond, corundum and staurolite. Silicon carbide and fused aluminum oxide are synthetic materials that could also be used in place of garnet schist.

History

• The term garnet comes from the Latin word for pomegranate, which was granatum. The small red crystals of garnet embedded in the rock were thought to resemble loose pomegranate seeds. The original use for garnet schist was as garnet sandpaper.