Oligoclase is a species of plagioclase feldspar (see above). The variety used in jewellery is called sunstone or, less commonly, aventurine feldspar. It has reflective inclusions of red, orange, or green platy crystals, which give it a metallic glitter. Sunstone may be faceted or carved - often as cabochons.

Sunstone occurs in metamorphic and igneous rocks in Norway, the USA, India, the former USSR, and Canada.

Obsidian has been used since prehistoric times for making tools, weapons, masks, mirrors, and jewellery. The very sharp shards of the natural glass have been fashioned as blades, arrowheads, and daggers. Today most obsidian jewellery comes from North and Central America.