Aventurine's a form of quartz, characterised by its translucency and the presence of platy mineral inclusions that give a shimmering or glistening effect termed aventurescence. The most common colour of aventurine's green, but it may also be orange, brown, yellow, blue, or gray. Chrome-bearing fuchsite (a variety of muscovite mica)'s the classic inclusion, and gives a silvery green or blue sheen. Oranges and browns are attributed to hematite or goethite. Because aventurine's a rock, its physica… (More on Aventurine)