a·ven·tu·rine 
(ə-vĕnchə-rēn′, -rĭn) also a·ven·tu·rin (-rĭn)
(ə-vĕnchə-rēn′, -rĭn) also a·ven·tu·rin (-rĭn)n.
1. An opaque or semitranslucent brown glass flecked with small metallic particles, often of copper or chromic oxide.
2. Any of several varieties of quartz or feldspar flecked with particles of mica, hematite, or other materials. Also called sunstone.
[French, from aventure, accident (so called because of its accidental discovery or the randomness of inclusions in it); see ADVENTURE.]
a·ventu·rine′ adj.