basic

[Eng. bas (e); -ic.] 1. Chem.: Pertaining to a base; constituting a base and a salt. 2. Having the base in exce ; having the base atomically greater than that of the acid or that of the related neutral salt; a direct union of a basic oxide with an acid oxide. (Todd & Bowman.) basic rocks. Lithology, Chem., & Geol. In Bernard Von Cotta's cla ification, one of the two leading divisions of igneous rocks, whether volcanic or plutonic. It comprises those which are poor in silica, as distinguished from Acidic Rocks, which are rich in that mineral constituent. A somewhat analogous cla ification had been previously adopted by Bunsen, who called rocks akin to the Basic ones Pyroxenic [PYROXENIC], and those allied to the Acidic Rocks Trachytic [TRACHYTIC); but while the Pyroxenic division contains only 45 to 60 parts of silica, the Basic one has 55 to 80 parts. (Bernhard Von Cotta: Rocks , translated by Lawrence, ed. 1878, pp. 120, 356.)