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