Amethyst usually is a transparent variety of quartz that comes in shades of purple.
Some translucent to opaque amethyst is also found and the purplish zones alternate with white or grayish areas. Color zonation can be very intense in transparent, translucent and opaque varieties. Amethyst is the traditional birth stone for the month of February. Most of the amethyst that is used in the gem trade now comes from Brazil. Historically, the Ural Mountains in Russia produced many fine amethysts and thousands were acquired by Catherine the Great.