Obsidian: Igneous Rock
These durability concerns make obsidian an inappropriate stone for rings and bracelets. It is best suited for use in lowimpact pieces such as earrings, brooches, and pendants. Obsidian is also used in making opal doublets and opal triplets. Thin slices or chips of opal are glued to a thin slice of obsidian to make a composite stone. The black ...