SILICA SAND is the commercial name for sand composed almost entirely of
grains of quartz. Sand of this kind is mined in Illinois from the St.
Peter Sandstone in LaSalle and Ogle Counties. The coarser grains of the
sand are characteristically rounded and frosted. The frosting causes the
sand to look white.
Illinois silica sand has many uses. It is used just as it is mined for
molding sand in which metal castings are made, for lining industrial
furnaces, and for many other purposes. Some of the sand is washed to
remove the small amount of impurities present. The washed sand is used
for such purposes as making glass, for grinding plate glass smooth, for
sand blasting, for molding metal, as fracturing sand to increase the
production of oil wells. Some silica sand is ground to a fine powder and
used as a fine abrasive, as a filler in paint, and as an ingredient in
pottery, glazes, and enamel.
A specially prepared St. Peter sand, known throughout the world as
Standard Ottawa Testing Sand, is used to test the strength of cements
and as a laboratory standard in physical tests of other sands.