rhodonite

[Gr. rhodon =a rose; suff. -ite ( Min .).] Min .: A mineral crystallizing in the triclinic system, though its angles approximate to those of pyroxene. Hardne , 5.5-6.5; specific gravity, 3.43.68; luster, vitreous; color, shades of red; some varieties, greenish, yellowish; streak, white; very tough. Composition: Silica, 45.9; protoxide of manganese, 54'1=100, represented by the formula, MnOSiO2; the manganese is frequently partly replaced, however, by protoxide of iron, lime, and sometimes zinc. Dana distinguishes three varieties: (1) Ordinary, ( a ) crystallized, ( 6 ) granular, ma ive; (2) Calciferous (Bustamite), which contairs from 9 to 15 per cent. of lime; (3) Zinciferous (Fowlerite).