chalk

(chawk) [L. calx or cre‘ta]. Amorphous calcium carbonate; a white, lusterle , insoluble earth: slightly alkaline. See creta. French c magnesium silicate. prepared c. Sce cred a pre par at a. C.-stone, a gouty concretion, usually of the hands and feet: mainly composed of sodium urate, sometimes combined with various lime-salts.