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 (F116) HMS Amethyst (F116) HMS "Amethyst" was a modified "Black Swan"-class sloop of the Royal Navy. She was laid down by Alexander Stephen and Sons of Linthouse, Govan Scotland on 25 March 1942, launched on 7 May 1943 and commissioned on 2 November 1943, with the pennant number U16. After the Second World War she was modified and redesignated as a frigate, and renumbered F116. During World War II, "Amethyst" was deployed mostly on anti-submarine patrols and escort duties. On 20 February 1945 she attacked and sank the U-boat with depth charges. "U-1276" had just sunk , a . The action