Aventurine

Part of speech: noun (n.)

1. A kind of glass, containing gold-colored spangles. It was produced in the first place by the accidental (par aventure) dropping of some brass filings into a pot of melted glass.

2. A variety of translucent quartz, spangled throughout with scales of yellow mica. ~= feldspar, a variety of oligoclase with internal firelike reflections due to the presence of minute crystals, probably of hematite; sunstone.