Amethyst is a violet variety of quartz often used in jewelry. The name comes from the ancient Greek meaning “not intoxicated”. The ancient Greeks wore amethyst and made drinking vessels decorated with it in the belief that it would prevent intoxication. It is one of several forms of quartz.
Amethyst is a purple variety of quartz (SiO2) and owes its violet color to irradiation, iron impurities and the presence of trace elements, which result in complex crystal lattice substitutions. The hardness of the mineral is the same as quartz.
The best varieties found in Siberia, Sri Lanka, Brazil and the far East. The ideal grade called “Deep Siberian”. It has a primary purple hue of around 75–80%, with 15–20% blue and (depending on the light source) red secondary hues.