- prepared c. purified native calcium carbonate, usually molded into cones; used as a mild astringent and antacid.
* * *
chalk 'chȯk n a soft white, gray, or buff limestone composed chiefly of the shells of foraminifers and sometimes used medicinally as a source of calcium carbonate called also creta see PRECIPITATED CHALK, PREPARED CHALK
chalky 'chȯ-kē adj
* * *
(chawk) [L. calx] 1. a natural calcium carbonate; the amorphous remains of minute marine organisms deposited on the sea bottom and decomposed by the action of acids and heat. Used as a polishing agent in dentistry and frequently as an ingredient in dentifrices. 2. any of various other substances physically resembling calcium carbonate.Medical dictionary. 2011.