Emily Dickinson Lexicon

CHALK, n. [chauk; Sax. cealc; D. Dan. and G. kalk; Sw. kalck; W. calc; Corn. kalch; Ir. cailk; L. calx; Fr. chaux. The Latin calx is lime-stone, chalk-stone, and the heel, and calco is to kick and to tread. In Italian calca is a crowd. The sense then is a mass made compact, a clod or lump. If the Gr. χαλιξ, flint, gravel, is the same word, the Latins deviated from their usual practice in writing calx; for chalx. These words are probably connected in origin with callus.]

A well known calcarious earth, of an opake white color, soft and admitting no polish. It contains a large portion of carbonic acid, and is a subspecies of carbonate of lime. It is used as an absorbent and anti-acid. – Cleaveland. Nicholson. Kirwan. Aikin. Black chalk is a species of earth used by painters for drawing on blue paper. Red chalk is an indurated clayey ocher used by painters and artificers.