Aventurine is a stone in the quartz family. It gets it's colour from chrome inclusions, and has a slight shimmer - although I have to admit - in the stones we have here - it is very subtle. However, it is nicely translucent and a very cool, calming shade of green.
Metaphysically - Aventurine is said to be a stone of friendship and protection. It brings mental clarity and stimulates creativity. It also brings prosperity and it's green colour is strongly linked to wealth and prosperity and career success.