Amethyst is the purple variety of the common rock crystal, or quartz. It’s been known and used as a gemstone since antiquity. The ancient Greeks and Romans thought that it could help prevent drunkenness, and wore jewelry made of amethyst or drank from vessels carved from amethyst. The color of amethyst can range from a very light violet-pink (“Rose de France”) to a very deep purple. The finest amethyst will show flashes of red and blue in a traditionally faceted stone; deep purple amethyst with this effect can be quite valuable as it is relatively rare.
There are no named varieties or species of amethyst.
Where is it found
Amethyst is found in a wide variety of locations around the world. The most significant economic deposits are in Brazil, Uruguay and Zambia. Siberia historically has produced some very fine deep purple amethyst. In the US, Georgia has produced some remarkable gem-grade amethyst and the Four Peaks region of Arizona is famous for its deep-colored amethyst deposits.
Amethyst is typically untreated. However, it can occasionally be heated to lighten the color slightly, or to turn it into the more rare and valuable ametrine.
Use in jewelry
Because it is relatively common and has good hardness (7 on the Mohs scale), amethyst is very popular in jewelry. Gems can often be found in larger sizes and are used in carvings as well as traditional faceted gems.
You can look at my current inventory of loose gemstones online here: http://www.earthstreasury.com/product-category/gemstones/quartz/amethyst-quartz/