Tăch'y-līte, n.

(49), n. [Gr. ταχύς, quick, λύειν, to dissolve, and λίθος, stone.] (Min.) A mineral of a velvet-brown or black color, and vitreous or greasy luster, consisting chiefly of silica, alumina, protoxide of iron, lime, magnesia, soda, and potash. Dana.