Amethyst
Amethyst is a transparent variety of quartz that ranges from a pale lilac color to deep purple color.
Popularity
Amethyst is one of the most popular purple gemstones in the world. Its rich color makes it an excellent gemstone for collecting or jewelry making. Amethysts have been admired since the days of Alexander the Great (336-323 B.C.)
Birthstone of February
Amethyst is the official February birthstone. Amethyst crystals are known for their healing and protective qualities. In fact, the word Amethyst comes from the greek word amethystos which means "cure to drunkenness".
Value
Amethysts were once as expensive as emeralds and rubies until large deposits were found in South America and Africa. Now one can pick up a high quality faceted amethyst gemstone for around $10-15 per carat. Although larger amethysts are valued higher because of their weight, their price per carat generally stays the same. E.g.
10 carat @ $10 per ct = $100
100 carat @ $10 per ct= $1,000