Description Ametrine Tumbled Stones have a Trigonal crystal system and is in the mineral class of Oxide in the Quartz group. It is a unique crystal that unites the Amethyst and Citrine color zones clearly defined and separated within the crystal. Ametrine is formed hydrothermally from silicic acid solutions that contain iron. To my knowledge, the world’s only source of this bicolored natural quartz is the Anahi Mine located in the jungles of Bolivia. Orinally they were secretly smuggled across the border to Brazil and sold as Brazilian products. In 1989 the rghts to the mine were sold, the Bolivian government changed, and since then these collectible gems became available on the domestic marketplace.
