Main Entry: ba·salt

Pronunciation: \bə-ˈsȯlt, ˈbā-ˌ\

Function: noun

Etymology: Latin basaltes, manuscript variant of basanites touchstone, from Greek basanitēs (lithos), from basanos touchstone, from Egyptian bḫnw

Date: 1601

: a dark gray to black dense to fine-grained igneous rock that consists of basic plagioclase, augite, and usually magnetite

— ba·sal·tic \bə-ˈsȯl-tik\ adjective