Chalk is a pure soft limestone, opaque white, and usually formed by the accumulation of the shells of foraminifera together with those of larger marine organisms. Chalk is found in large quantities in land masses which were at one time covered by the sea. Chalk is composed of between 50 and 98 percent calcium carbonate and various of minerals including clay, hematite, mica, quartz and pyrite. Chalk is important in industry and is used in the manufacture of rubber goods, paint, putty, polishing powders, cement, as well as the familiar writing implements beloved by school teachers. Research Chalk
Abbreviations
Rocks & Minerals
Research Chalk