Aventurine

A·ven·tu·rine

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.
A variety of translucent quartz, spangled throughout with scales of yellow mica. (Min.)

Aventurine feldspar: a variety of oligoclase with internal firelike reflections due to the presence of minute crystals, probably of hematite; sunstone.