argillyte, targillite

[Gr.ἄργιλλος ( argillos ) white clay; and sufl. -yte, given by Dana to rocks, as contradistinguished from nunerals, which receive the termination -ite. Both are from Gr. ιτης ( ites ) = of the nature of.] Another name for Clay Slate (q.v.). " Argillyte and talcose schist generally contain more or le of orthoclase in a crypto-crystalline or undistinguishable state. -Dana . Min ., 5th ed., p. 539.