alkalicalcic

Century Dictionary and Cyclopedia

1. In petrography, a term used in the quantitative classification of igneous rocks to indicate that certain rocks, the chemical composition of which is known, contain alkalis and lime belonging to the standard salic minerals (feldspars and feldspathoids) in equal or nearly equal amounts. A certain systematic division of the quantitative classification is called the alkalicalcic rang. See quantitative classification of igneous rocks, under rock.