Sands of Extreme Southern Illinois
In southern Illinois deposits of sand laid down in an arm of the ocean that once extended northward into Illinois from the Gulf of Mexico are found in Alexander, Union, Pulaski, Pope, and Massac Counties. The deposits are commonly a light color—white, cream, yellow, or gray.
The grains of the sand are almost all quartz and generally are angular. Some of the sands are of almost powder-like fineness, others are fine or medium grained. Many of the sands contain flakes of white mica, a glistening, silvery-looking mineral often mistaken for silver or platinum. Unlike these metals, however, mica is comparatively light in weight and is not metallic. Also present in some sands are small flakes of the mineral graphite.
The southern Illinois sands have not been widely used, but some of them have been employed in making concrete. They also may have possibilities for molding and core sand.
As a result of work by Survey geologists, the location and properties of many of the southern Illinois sand deposits are known.