aventurine
Concise Oxford English Dictionary © 2008 Oxford University Press:
aventurine /əˈvɛntʃərɪn/
▶noun
- 1 brownish glass containing sparkling particles of copper or gold.
- 2 translucent quartz or feldspar containing small reflective mineral particles.
– origin C18: from Fr., from Ital. avventurino, from avventura ‘chance’ (because of its accidental discovery).
'aventurine' also found in these Oxford entries:

