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. [1913 Webster]
A variety of translucent quartz, spangled throughout with scales of yellow mica. [1913 Webster]
Aventurine feldspar, a variety of oligoclase with internal firelike reflections due to the presence of minute crystals, probably of hematite; sunstone.
, n. Mineral.
1 brownish glass or mineral containing sparkling gold-coloured particles usu. of copper or gold.
2 a variety of spangled quartz resembling this.
Etymology
F f. It. avventurino f. avventura chance (because of its accidental discovery)