\Bas"a*nite\, n. [L. basanites lapis, Gr. ? the
touchstone: cf. F. basanite.] (Min.)
Lydian stone, or black jasper, a variety of siliceous or
flinty slate, of a grayish or bluish black color. It is
employed to test the purity of gold, the amount of alloy
being indicated by the color left on the stone when rubbed by
the metal.