The purple amethyst has long been the color of royalty and wealth so it is not surprising that amethyst has been so much in demand during history. In the 10th century Constantine VII was surnamed Porphyrogenitus, "born to the purple", a term for a son born to a reigning monarch.  The English Royal Scepter and the Prince of Wales coronet are studded with amethysts. Catholic bishops wear amethyst rings and drink from ceremonial Amethyst cups. Because amethyst was thought to encourage celibacy and symbolize piety, amethyst was very important in the ornamentation of Catholic and other churches in the Middle Ages.  It was, in particular, considered to be the stone of bishops and bishops still often wear amethyst rings.  Leonardo Da Vinci wrote that amethyst was able to dissipate evil thoughts and quicken the intelligence (it obviously worked pretty well for him!)

Mythology & Lore:

This gemstone's name comes from the Greek word "amethustos" which means, "not to intoxicate". The ancient Greeks believed that whoever wore this stone was protected from inebriation. This idea stems from the myth that Bacchus, the god of wine and conviviality, in a fit of anger, swore that tigers would eat the first person that crossed his path. The maiden, Amethyst, was on her way to worship the goddess Diana who rescued her by turning her to stone. Then Bacchus, full of remorse, poured wine over the stone and created the purple gem named amethyst. Many believe that wearing amethyst will safeguard soldiers in war, ensure victory, control evil thoughts, and sharpen intelligence. Roman women even claimed that the gem could keep their husbands from straying!

Sources: 

Amethyst, transparent purple quartz, is the most important quartz variety used in jewelry. A major reason for their popularity in jewelry design is their wide availability and modest price. Today the two main sources of amethyst come from Brazil and Zambia. . Amethyst is mined in Brazil, Uruguay, Bolivia and Argentina in South America and Zambia, Namibia, and other African countries.

Choosing an Amethyst:

 Generally, amethyst from South America tends to be available in larger sizes than African amethyst but amethyst from Africa has the reputation for having better, more saturated, color in small sizes.  Very dark amethyst, mostly in small sizes, is also mined in Australia.  The preferred African amethyst, though less plentiful and smaller than Brazilian, comes in a beautiful deep purple with reddish overtones. 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.

Care & Maintenance: 

Amethyst is a durable and lively gemstone that is appropriate for all jewelry uses.  It should be cleaned with a mild soap and water mixture.