Obsidian :: Obsidian (n.) A kind of glass produced by volcanoes. It is usually of a black color, and opaque, except in thin splinters..
Obsign :: Obsign (v. t.) To seal; to confirm, as by a seal or stamp..
Obsignation :: Obsignation (n.) The act of sealing or ratifying; the state of being sealed or confirmed; confirmation, as by the Holy Spirit..