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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.
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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.
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