Amethyst with Calcite in Semi-Polished Agate Geode, Uruguay
16.25" x 10" x 10.5" / 52.5 lbs
Amethyst (SiO2) is a purple variety of quartz. This specimen also contains agate, a cryptocrystalline variety of silica, chiefly chalcedony. The characteristic purple color is created when trace amounts of iron are irradiated (from the natural radiation in rocks). This museum-quality specimen was mined in the northern region of Uruguay’s Artigas Department, the premier source of fine quality amethyst. Collected by Cory Cotter, PhD (2016).