Amethyst is not primarily defined by carat weight; this is different to most gemstones where the carat weight exponentially increases the value of the stone. The biggest factor in the value of amethyst is the color displayed. The highest grade amethyst (called "Deep Russian") is exceptionally rare and therefore, when one is found, its value is dependent on the demand of collectors. It is, however, still orders of magnitude lower than the highest grade sapphires or rubies (padparadscha sapphire or "pigeon's blood" ruby). Amethyst Amethyst is a violet variety of quartz. The name comes from the Koine Greek ἀμέθυστος "amethystos" from
Amethyst Germany. In the 19th century, the color of amethyst was attributed to the presence of manganese. However, since it can be greatly altered and even discharged by heat, the color was believed by some authorities to be from an organic source. Ferric thiocyanate has been suggested, and sulfur was said to have been detected in the mineral. Synthetic (laboratory-grown) amethyst is produced by a synthesis method called hydrothermal growth, which grows the crystals inside a high-pressure autoclave. Synthetic amethyst is made to imitate the best quality amethyst. Its chemical and physical properties are the same to that of natural amethyst