Aventurine is a slightly translucent to opaque variety of microcrystalline quartz; it contains tiny inclusions of shiny materials which is what gives the stone a sparkling effect known as aventurescence. Inclusion that consist of mica will give a silvery shimmer, while inclusions of hematite will give a reddish or gray sparkle.
Common aventurine ranges in color from green, to brown, peach, yellow and red; there is even a blue aventurine which is quite beautiful. Aventurine is often mistaken for amazonite, jade and even chalcedony when the coloring is creamy enough.
Interestingly enough the name of the stone was derived from a happy accident. Sometime during the eighteenth century, Venetian glass workers were preparing molten glass when copper filings accidentally fell into the batch producing a sparkling glass product. The name aventurine comes from the phrase “a ventura” which means “by chance”.
This is also how goldstone came about, and many have attempted to simulate aventurine in the same fashion as goldstone.
Some of the earliest most primitive stone tools (such as axes) fashioned by the ancestors of man over two and a half million years ago were made of quartz varieties such as aventurine. These materials were used, no doubt for their hardness and isotropic brittleness which is what made it possible to shape the tools with relative ease and dexterity.