Min. [ad. L. basanītes (lapis), in Pliny, f. Gr. βάσανος touchstone, test.] A velvet-black siliceous variety of quartz, used on account of its blackness and hardness for testing the purity of precious metals, by means of the mark left after rubbing the metal upon it.
[1753. Chambers, Cycl. Supp., Basanites … the touchstone used for trying gold.]
1794. Kirwan, Min., I. 307. Basanite. Lydian stone of Werner. Black Jasper of some.
1850. Leitch, Müller’s Anc. Art, § 403. Statue of the Nile … of basanite.
