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) HMS Amethyst (1799) HMS "Amethyst" was a Royal Navy 36-gun "Penelope"-class fifth-rate frigate, launched in 1799 at Deptford. "Amethyst" served in the French Revolutionary Wars and the Napoleonic Wars, capturing several prizes. She also participated in two boat actions and two ship actions that won her crew clasps to the Naval General Service Medal. She was broken up in 1811 after suffering severe damage in a storm. "Amethyst" was commissioned in May 1799 under the command of Captain John Cooke. She then operated on the Dutch coast later that year. During the Anglo-Russian invasion of Holland, "Amethyst" conveyed the Duke