Obsĭus, i, m.,
I a Roman surname , Plin. 36, 26, 67, § 196.
II —Hence, Obsĭānus , a, um, adj., belonging to Obsius : lapis, so named after the discoverer , Plin. 37, 10, 65, § 177.— Also subst.: obsĭāna , ae, f., Plin. 37, 13, 76, § 200; and obsĭāna , ōrum, plur. n., a kind of glass : obsiana numerantur, id. 36, 26, 67, § 196. (The older editions of Pliny read Obsidius and Obsidianus; hence the name obsidian applied to the stone.)