From the family of Quartz, green amethyst have naturally been found. Speculations are that heat produced by geological events cause the production of natural green deposits. Natural prasiolite crystals are often dichroic, meaning they appear as different colors when observed under different lighting.
In most cases they are heat treated. The green in green Amethyst comes when heat is applied to it, usually Amethyst will turn yellow, brown or orange but the Amethyst containing specific properties of iron will turn green.
Green Amethyst also called Prasiolite has a hardness of 7 on the Mohs scale and like all Quartz are composed of silicon dioxide (SiO2). Durable and scratch-resistant enough for daily wear, they are perfect for jewelry and can make a spectacular statement in large carats.