Aventurine or aventurine is a green to reddish-brown colored variety of the mineral quartz. Usually this gemstone comes in the green and cut variant. Aventurine has a hardness of 7 and is found in Russia in the Urals and China. Aventurine, like many other varieties of quartz (for example, amethyst and rose quartz) is cut so that it can be used as jewelry. The chemical composition of aventurine is SiO2 KAl2 (OH, F) 2 / AlSi3O10 Cr. The Ancient Greeks sewed aventurine into a warrior's clothing to maintain his courage, ambition, and optimism.