Naturally occurring green amethyst is also called prasiolite. The name is derived from the Greek words "prason" and "lithos," which means "leek stone." So, when discovered, the green color resembled the shades of the leek and other vegetables. Natural stones are rare, but the growing popularity of the stone prompted laboratory heat-treatments to expand the availability. Another treatment that is being done to achieve green-colored quartz is irradiation. This process uses colorless quartz and produces lighter shades of green. It is also less expensive than prasiolite or green amethyst. This gem is natural,untreated and should not be confused with the abundant material on the market mostly irradiated. From Brazil.