basalt

noun

1. a dark, fine-grained, usually extrusive igneous rock that is more basic than andesite, consisting chiefly of plagioclase feldspars and pyroxene: often found in vast sheets, it is the most common extrusive igneous rock
2. a kind of unglazed, black pottery designed by Josiah Wedgwood
   also basaltware

Origin: earlier basaltes < L, a dark Ethiopian marble: term used by Pliny for basanites < Gr basanitēs, species of slate used to test gold < basanos, touchstone, test (ult. < Egypt bḫnw) + -itēs, -ite