Amethyst comes from the Greek word amethystos, meaning not drunken. Amethyst was esteemed by Greek and Roman cultures not only for its believed ability to guard against intoxication, but also for granting its possessor a sharp wit. Its hues vary from a pure, and valuable, purple to a pale violet that is sometimes accompanied by faint blue and green hues. Its primary source is Brazil and other South American countries. Until the discovery of these sources just a couple hundred years ago, amethyst was valued as highly as ruby, sapphire, and emerald. It is a variety of quartz which can also be found in yellow, golden, or orange; when found in these colors, it is known as citrine. Furthermore, amethyst and citrine may form in the same crystal, which is then known as ametrine. Quartz may also be green, which is named prasiolite.