Amethyst element impurities), and the presence of trace elements, which result in complex crystal lattice substitutions. The hardness of the mineral is the same as quartz, thus it is suitable for use in jewelry. Amethyst occurs in primary hues from a light pinkish violet to a deep purple. Amethyst may exhibit one or both secondary hues, red and blue. The best varieties of amethyst can be found in Siberia, Sri Lanka, Brazil and the far East. The ideal grade is called "Deep Siberian" and has a primary purple hue of around 75–80%, with 15–20% blue and (depending on the light source)
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