Amethyst is the traditional birthstone for the month of February.
(I remember being jealous as a kid, since there were purple stones for February but October always got something pink instead of opal or even fake opal!)
Iron impurities in quartz give amethyst its wonderful purples-from pale lilac to royal.
Sometimes you can see what look like pieces of lighter and darker amethyst in the same gem, this is pretty common and is called color zoning. It often appears as bands or stripes of color parallel to the face of the stone. So the trick in cutting them is to take advantage of the strips for striking effect or else make the stone look solidly the same color even if it isn’t.
Amethyst was rare and valued with rubies and emeralds until the 19th century when amethyst deposits were discovered in Brazil.
Historically most came from mines in Russia and India, today most come from Brazil and Zambia. Since amethyst can be found in large crystals the cost does not increase exponentially per carat the way most gemstones do. Instead the first consideration for value is color. The richer and purer the color, the higher the value. Siberian mines once produced the best gems and even now the best gems, no matter where they were mined, are called ‘Siberian.’
Amethyst is one of the oldest known gemstones, human use dating back over 4000 years. The ancient Egyptians used it in jewelry, the Greeks associated it with Dionysus, the Romans carved amulets out of it, and amethyst beads have been found in Anglo-Saxon troves. Since the Middle Ages bishops traditionally wore amethyst rings and there is an enormous amethyst under the cross on the scepter in the British crown jewels.
There are two not really myths about amethyst that you might have heard. One was written by a French poet named Remy Belleau in the 16th century and the other seems to be a folklore variation that evolved from it. In original poem Bacchus was pursuing a young woman named Amethyste who refused him and prayed to Diana to be saved. Diana saved her by turning her into a white rock. Bacchus poured his wine on the rock and turned it purple to honor her. The modified version involves him being angry and catching an innocent young woman in a trap to satiate his anger, and ends the same with prayers to Artemis and white rock being stained with purple wine.