trachybasalt

[ trey-kee-buh-sawlt, -bas-awlt, -bey-sawlt, trak-ee- ]
/ ˌtreɪ ki bəˈsɔlt, -ˈbæs ɔlt, -ˈbeɪ sɔlt, ˌtræk i- /

noun

a fine-grained volcanic rock containing sanidine and calcic plagioclase.

Origin of trachybasalt

First recorded in 1885–90; trachy- + basalt