Gemstone Glossary

Sandstone

Sandstone is actually a sedimentary rock consisting of cemented grains of quartz. It is named for the sand-sized grains of quartz of which the rock is composed. Sandstone is formed deep underground. With a great deal of heat and pressure, small grains are transformed into a tough rock with tightly packed mineral grains. Sandstone is commonly found in gray, buff, red, or brown although green, yellow, white and some other colors are also found.


The usual cementing material in sandstone is calcium carbonate, iron oxides, or silica. There are many varieties of sandstone in existence, its varieties are distinguished by variations in color and hardness and texture. These variations depend largely on the cementing material. Those that contain iron oxide are red to reddish brown. Those containing silica or calcite as the binding material will be light in color, usually a pale yellow, buff or white to gray. Green sandstone often contains, in addition to sand and glauconite, fossil shells and iron oxides.

Sandstone is a common mineral in the earth’s crust and is found in large quantities worldwide. It is found in association with most other sedimentary rocks. Sandstone is widely used in construction and industry. It may be crushed to form loose sand grains, which can then be put to the same industrial uses as sand. With its variety of textures and colors, sandstone also enjoys its place in the semi-precious stone market. It is used extensively in carvings as well as being cut into spheres and cabochons.