Amethyst is a violet variety of quartz often used in jewelry. The name comes from the Ancient Greek 'amethystos' which means "not intoxicated" a reference to the belief that the stone protected its owner from drunkenness; the ancient Greeks and Romans wore amethyst and made drinking vessels of it in the belief that it would prevent intoxication. It is one of several forms of quartz. Amethyst is the traditional birthstone for February.

Amethyst is the purple variety of quartz (SiO2), containing an impurity of iron, which gives the violet color to the mineral. The hardness of the mineral is the same as quartz's, thus it is suitable for use in jewelry.

Amethyst ranges in color from a light pinkish violet to a deep purple. The ideal grade is called "Deep Siberian"

Of very variable intensity, the color of amethyst is often laid out in stripes parallel to the final faces of the crystal. One aspect in the art of lapidary involves the correct cutting to place the color correctly in order to make the tone of the cut stones homogeneous. The fact that sometimes only a thin surface layer of violet color is present in the stone, or that the color is not homogeneous often makes for a difficult cutting.


Gem quality amethyst is a relatively inexpensive gemstone often used in jewelry.  Amethyst mineral

 specimens, geodes and large cathedrals are prized by collectors.


When amethyst is heated, it becomes CITRINE, a yellow or orange variety of quartz.


 

For more information try these links:

http://www.minerals.net/mineral/amethyst.aspx

http://www.quartzpage.de/amethyst.html