Aventurine is a form of Chalcedony Quartz that is known for its small shiny inclusions that can resemble tiny gold flecks. The glistening effect of the inclusions is known as aventurescence. Aventurine is typically some shade of green, but brown, orange, and gray Aventurine can also be found, although these varieties are rarely used as gemstones. The aventurescence effect can range from being very weak and barely visible to very strong, and the strength of the shimmering effect depends on the concentration and size of the inclusions within the gemstone. Aventurine is known to bear resemblance to Sunstone (which used to be known as Aventurine Feldspar), but the latter gemstone variety is typically red or orange rather than green.
Etymology & Sources
Aventurine was discovered in Italy in the 18th century. The material was supposedly discovered by chance, and the Italian for ‘by chance’ is ‘a ventura’ – this is how the name Aventurine came about. Aventurine can be found in many places around the world, and common sources of the material include India, Brazil, Austria, Russia, Chile, and Tanzania.
Aventurine is most commonly green, and while brown, grey, and orange varieties exist they are uncommon and usually not used for decorative or gemstone purposes. The gemstone often displays uneven coloring, which is caused by the same inclusions that cause the aventurescence. Aventurine can range from translucent to opaque and has a waxy or vitreous luster. In its natural form, Aventurine can be grainy, but this is remedied with polishing.
Aventurine has similar hardness to other Chalcedony Quartz varieties, and measures a 7 on the Mohs scale. It has specific gravity of 2.65-2.70, and has a refractive index of about 1.55.
Aventurine is typically not faceted into the traditional gemstone shapes – most commonly it is cut en cabochon, and is occasionally found in other rounded shapes like ovals, teardrops, and others. It is also sometimes used for carvings or other decorative pieces. Jewelry hobbyists can also find Aventurine in bead form for jewelry making purposes. Aventurine is reasonably hard and is quite affordable, so it can be used for more or less any kind of jewelry application.
Aventurine is typically not treated or enhanced in any way. However, there are some artificial non gemstone materials that can appear quite similar to Aventurine – the most well known of which is Goldstone, which is a kind of glass produced in Italy.