Amethyst, the royal gem 

Amethyst is the purple variety of quartz and is a popular gemstone. With its luscious color, it is the official birthstone for February. The name "amethyst" comes from the Greek and means "not drunken." This was maybe due to a belief that amethyst would ward off the effects of alcohol, but most likely the Greeks were referring to the almost wine-like color of some stones that they may have encountered.

The color purple is traditionally the color of royalty and amethyst has been used since the dawn of history to adorn the rich and powerful monarchs and rulers. Fine amethysts are featured in the British Crown Jewels and were also a favorite of Catherine the Great and Egyptian royalty. Amethyst, transparent purple quartz, is the most important quartz variety used in jewelry. 

Its color is unparalleled.  Amethyst ranges in color from pale lilac to deep purple. The pale colors are sometimes called "Rose de France" and can be seen set in Victorian jewelry. The deep colors are the most valuable, particularly a rich purple with rose flashes.  Although it must always be purple to be amethyst, it can and does have a wide range of purple shades. 

Amethyst Quartz - Mixture of Amethyst and Milky Quartz (or clear Quartz). It is purple on top and white or clear on the bottom. It may also be banded purple and white.
Ametrine - Mixture of Amethyst and Citrine.  It is partially purple and partially orange-yellow, with the color zones often sharply divided.
Canadian Amethyst - Amethyst with an internal coating of red Hematite. It is only found in Thunder Bay, Ontario.
Lavender Amethyst - Pale purple variety of Amethyst.
Vera Cruz Amethyst - Tall, prismatic Amethyst crystals from Vera Cruz, Mexico.

Amethyst is mined in Brazil, Uruguay, Bolivia, Argentina, U.S.A, Canada, Mexico, Zambia, Namibia and other African countries.