Amethyst is a well known mineral and gemstone. It is the purple variety of the mineral Quartz, and its most valuable and prized variety. Its name derives from the Greek "amethystos", which means "not drunken", as Amethyst in antiquity was thought to ward off drunkenness. The color of some Amethyst specimens from certain localities slowly fade upon prolonged exposure to light. When used as a gemstone, Amethyst is often heat treated to deepen the color, or to transform it into Citrine. Some varieties may also change to a light green color, which is given the trade name "Prasiolite", or "Green Amethyst", as it is more commonly known in the gem trade.

 

Amethyst is most prevalent as small stubby pyramidal crystals, although several localities such as the Mexican occurrences are well-known for producing elegantly tall prismatic crystals, which are very highly regarded by collectors. Amethyst also forms the internal lining of geodes, some of which can be over 10 feet tall and weighing several tons.

Color 

Light to dark purple. Sometimes banded with purple and whitish lines. May also be mixed together with Citrine. 

Crystal Forms and Aggregates 

Most often as protruding clusters of pyramids on a matrix base. These "pyramids" can be quite large. Also occurs as tall prismatic crystals, as short stubby crystals, in drusy aggregates, massive, in geodes, and as rounded waterworn stones. A very interesting habit is as crystalline crusts inside volcanic pipes. Crystals are usually striated horizontally, and occasionally have a scepter growth. 

 

 

VARIETIES    

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 yellow or orange, with the color zones often sharply divided. More information can be found on the Ametrine gemstone page. 

Cactus Quartz  -  Form of Quartz, usually Amethyst, Citrine, or a combination of the two, that contains a large crystal or crystals overgrown with a layer of spiky smaller crystals. Cactus Quartz is specific to Boekenhoutshoek (Magaliesberg) in South Africa. 

Canadian Amethyst  -  Amethyst with an internal coating of red Hematite under the crystal surface, found near Thunder Bay, Ontario, Canada. 

Lavender Amethyst  -  Pale purple variety of Amethyst. 

Veracruz Amethyst  -  Tall, prismatic Amethyst crystals from Vera Cruz, Mexico. 

 

USES   

Amethyst is one of the most popular gems. It has a beautiful color and is fairly common, making it an inexpensive and widely used gem. Most Amethyst is faceted into jewelry cuts, and some are cut as cabochons. Large, massive chunks of Amethyst banded with Quartz is sometimes carved into ornaments.

Amethyst is also very popular among mineral collectors. Small geode sections and tumbled stones are sold to amateur collectors, while more serious collectors go for the rare prismatic crystals and giant geode sections.