Amethyst of synthetic quartz is used. Treated amethyst is produced by gamma ray, X-ray or electron beam irradiation of clear quartz (rock crystal) which has been first doped with ferric impurities. On exposure to heat, the irradiation effects can be partially cancelled and amethyst generally becomes yellow or even green, and much of the citrine, cairngorm, or yellow quartz of jewelry is said to be merely "burnt amethyst". The Greek word "amethystos" may be translated as "not drunken", from Greek "a-", "not" + "methustos", "intoxicated". Amethyst was considered to be a strong antidote against drunkenness, which is why wine goblets were
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