The United States boasts a legendary mineralogical tradition, with some of the most iconic locations in the world. From the native copper nuggets of Michigan, unique in shape and crystallization, to the spectacular turquoise of Arizona, prized in jewelry for centuries, to the celebrated fire agates of northern Mexico and the American Southwest, renowned for their internal iridescence. There are also amethyst quartz from Colorado, fluorites from Illinois, opals from Nevada, beryls from Utah, and numerous crystals of gypsum, calcite, and aragonite in magnificent formations.