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)
Amethyst Incident Half an hour later her signals ceased, though she was making a second attempt to take the "Amethyst" in tow, having turned downstream again. This attempt also failed and she sustained further damage and casualties during which her steering was affected. She therefore had to continue downstream out of the firing area with 10 men killed and 23 wounded. "Amethyst" was re-floated just after midnight, on 21 April, after lightening the ship, and she moved up river. The Assistant British Naval Attaché, Lieutenant Commander John Kerans, joined the ship on 22 April after he had dealt with all the wounded