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) the Île de France some nine weeks earlier and was sailing for Bordeaux with a cargo of cotton, coffee, tea, sugar, indigo, and the like. Still in company with "Nymphe", "Amethyst" captured "Julius Pringle" and recaptured "Active" (4 March) and "Amity" (21 March). Then on 31 March, "Amethyst", with "Nymphe", captured the French privateer "Mars". "Mars" was armed with twenty 12-pounder guns and two 36-pounder obusiers, and carried a crew of 180 men. Cooke described her as being "one of the finest Privateers fitted out of Bourdeaux." The British took "Mars" into service as . "Amethyst" also captured a valuable