Worlds Biggest Amethyst Geode (The Empress Of Uruguay): Standing majestically at nearly 11 feet tall and weighing the same as a Cadillac Escalade, The Empress of Uruguay is billed as the world's largest amethyst geode. The exposed interior radiates with tens of thousands of deep purple, gem-quality amethyst crystals and is the top attraction at the Crystal Caves Museum in Atherton, Australia. Amethyst is the official birthstone for February babies, and there is no example of the gem more impressive than this 5,500-pound geode. The Empress of Uruguay was discovered in the Artigas region in northern Uruguay, a mining area famous for yielding some of the world's finest-quality amethysts.