Crystals of Amethyst the purple to violet variety of quartz, are encountered in vugs located in hydrothermal quartz veins. alternatively, amethyst crystals are often found lining the central cavities of the agate geodes often associated with basalt flows. The name is belived to be derived from the greek word amethustos, which can be translated as 'not drunken' ( see bullet point). many fine example of amethyst are mounted in the rings of bishop. In the 19th century russian production set the halmark for superb amethyst and even today fine violet material with distinect underlying port wine tones may be described as siberian amethyst. Brazil and Zambia are currently the major producers of gem quality amethyst.