Black chalk

Chalk Chalk (ch[add]k), n. [AS. cealc lime, from L. calx limestone. See {Calz}, and {Cawk}.] 1. (Min.) A soft, earthy substance, of a white, grayish, or yellowish white color, consisting of calcium carbonate, and having the same composition as common limestone. [1913 Webster]

2. (Fine Arts) Finely prepared chalk, used as a drawing implement; also, by extension, a compound, as of clay and black lead, or the like, used in the same manner. See {Crayon}. [1913 Webster]

{Black chalk}, a mineral of a bluish color, of a slaty texture, and soiling the fingers when handled; a variety of argillaceous slate.

{By a long chalk}, by a long way; by many degrees. [Slang] --Lowell.

{Chalk drawing} (Fine Arts), a drawing made with crayons. See {Crayon}.

{Chalk formation}. See {Cretaceous formation}, under {Cretaceous}.

{Chalk line}, a cord rubbed with chalk, used for making straight lines on boards or other material, as a guide in cutting or in arranging work.

{Chalk mixture}, a preparation of chalk, cinnamon, and sugar in gum water, much used in diarrheal affection, esp. of infants.

{Chalk period}. (Geol.) See {Cretaceous period}, under {Cretaceous}.

{Chalk pit}, a pit in which chalk is dug.

{Drawing chalk}. See {Crayon}, n., 1.

{French chalk}, steatite or soapstone, a soft magnesian mineral.

{Red chalk}, an indurated clayey ocher containing iron, and used by painters and artificers; reddle. [1913 Webster]