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 (1903) was begun. The squadron returned to the Port of Bahia without success. A further attempt to find "Möwe" was made on 24 January when "Amethyst" was joined by , but this was also unsuccessful. Patrols to search for German surface raiders were also conducted in April and May 1917. After a long stay in Rio de Janeiro, "Amethyst" sailed on 5 April 1918, patrolling down the coast inspecting vessels and arriving in Montevideo on 10 March. On 31 May 1918 "Amethyst" left Bahia, Brazil to return to Devonport. On the way home, she met off the coast of Sierra Leone