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 Mountain exposures of well known and visited petrified forests. The summit of Amethyst Mountain is traversed by Specimen Ridge Trail, which also traverses the south side of Specimen Ridge between Tower Junction and Soda Butte Creek and through the Yellowstone Petrified Forest. Amethyst Mountain consists of a geological formation known as the Lamar River Formation. Within the Amethyst Mountain area, it is over thick and consists predominantly of conglomerate and lesser proportions of tuffaceous sandstone and siltstone. Volcanic breccia is absent and only a very few thin airfall volcanic ash beds have been identified in the exposures at Amethyst Mountain. The