Nasr Bros Jewelers

Amethyst is the most precious stone within the quartz group. Since purple is considered a royal color, amethyst the transparent purple quartz, enjoyed an historical importance as an insignia of power. Fine amethysts are featured in the British Crown Jewels and were also a  favorite of Catherine the Great and Egyptian royalty. Amethyst was also a favorite stone in the high ranks of the Christian church and was referred to "the stone of bishops". The Greek word "amethystos translates into "not drunken." Amethyst was considered to be a strong antidote against drunkenness, which is why wine goblets were often carved from it. The gemstone still symbolizes sobriety.
Amethyst colors 

The color agent of amethyst is iron. The colors range from purple, violet to pale red-violet. So-called green amethyst is produced by heat treatment.

Buying Amethyst
The deep colors are the most valuable, particularly a rich purple with rose flashes. The "Siberian" deep purple with red and blue flash commands the highest prices. So-called green amethyst does not really count as amethyst, which is by definition violet or purple.

 In artificial light amethyst does not display its best color. It looks best in daylight, more precisely, particularly just after sunrise and before sunset, when the light is soft and warm. 
A fine amethyst is transparent, which means, the light passes through the stone unhindered. A translucent amethyst slightly weakens the passage of the light through the stone. The best quality amethyst is "clean", free of visible inclusions of any kind. As the amethyst is plentiful, there is little reason to buy stones with visible inclusions.

Due to the variability of the color distribution in the crystals, amethyst is often cut as brilliant round to maximize the color. Other cuts can be used when the color is better distributed. Amethyst is available in a wide range of calibrated sizes and shapes, including many fancy shapes.

Amethyst location and deposits 
The most important deposits are in Brazil, namely the "Palmeira" amethysts of Rio Grande do Sul and the "Maraba" amethysts of Para. Other deposits are found in Bolivia, Canada, India, Madagascar, Mexico, Myanmar (Burma), Namibia, Russia, Sri Lanka, United States (Arizona), Uruguay and Zambia.