DIAMOND

n. Di'a3-musnd. Gr., aSdfia*. L,a,t.,adam as. Fr., diamant. Ger., Diamant. It., Sp., diamante. A precious stone constituting one of the allotropic forms of carbon. It occurs in many crystalline forms, the fundamental form being that of an octahedron. It presents a brilliant, characteristic lustre, and is usually transparent and colorle , although it may exhibit various hues. It has a hardne surpa ing that of any other substance. When heated in air it is converted into carbon dioxide, and under the heat of the electric arc it is converted into black amorphous carbon. Its sp. gr. is 3'5 to 3'6. [B, 81; " Proc. of the Am. Pharm. A oc.," xv, p. 192, 207 (B).] Anthracitic d., Black d. Syn., carbonado. A form of impure carbon resembling anthracite in appearance, but as hard as an ordinary d., and employed to cut d's. [B, 3; " Proc. of the Am. Pharm. A oc.,1' xxii (a, 21).] [s. 551]