Rough green adventurine. Image from http://www.gemselect.com/other-info/aventurine-gems.php
I had passed over this rock before and now it is getting its due. The name comes from the Italian “a ventura” meaning “by chance,” referring to the accidental creation of a manmade glass version of what would become known as aventurine. It is an allusion to the lucky discovery of aventurine glass, credited to a worker knocking a bucket of copper filings into some molten glass at a factory. The resulting material was so pretty the factory began making it on purpose, and there is a Miotti family in Italy that did very well selling such glass in the 17th century. Whether or not the story is true, many people consider aventurine a stone of good fortune. Gamblers historically carry aventurine in their left pocket to win the favor of Lady Luck, and the grey-green color understandably reminds people of dollar bills. It is also said to be able to bring one’s emotions into balance.
Aventurine is a variety of quartz and it usually contains flecks of mica or other minerals. Aventuresence is a trait in gemstones that refers to a glittering sheen created by light bouncing off of tiny inclusions. Aventurine occurs naturally in several colors based on these inclusions. Green is from fuschite (mica containing chromium), while red comes from hematite (iron oxide). Blues, grays, and creamy whites are also possible, but know that many stones on the market are actually manmade out of glass. The natural stone is also often treated with oils or dyes to give it a richer color. The vast majority of the green variety is mined in India, but aventurine is also mined in Germany, Austria, Spain, South Africa, and in pockets around the U.S. and Asia. Since it is essentially glass, some care should be taken, but it is a nice stone for the price.