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
HMS Amethyst (1799) Guadaloupe, and his suite. On 30 July, "Amethyst" and two other frigates, and , sailed from Plymouth for the Isle of wight. There they were to pick up Dutch troops that they were to return to Holland. On 10 September "Amethyst" captured the French lugger "Alert", and recaptured a ship. In October 1801 Captain Charles Taylor took command of "Amethyst", only to be replaced in the next month by Captain Henry Glynn, for the North Sea. During the Peace of Amiens, "Amethyst" sailed on anti-smuggling patrols off the coast of Scotland under the command of Captain Alexander Campbell. During the