- Tazna Mine (Tasna Mine; Tazna-Rosario Mine), Cerro Tazna, Atocha-Quechisla District, Nor Chichas Province, Potosi Department, Bolivia
- Small Cabinet, 6.1 x 5.5 x 5.3 cm
This piece came from the great find of Ferberite twins of 2003. It is a rather large and impressive twinned crystal. This attractive specimen features the classic, "butterfly" twinning of Ferberite along the a (100) face. It is a good quality, sharp, lustrous, aesthetic, rarely seen doubly-terminated, jet-black twinned crystal. It has an attractive "open" or "butterfly" form and the twin itself is in great shape on the front and back save a few pocket contacts. Specimens like this are rare from any locality, including Tazna. Twinned Ferberite crystals from Bolivia are becoming increasingly difficult to obtain in recent years as the price of Tungsten ore has driven the miners to throw nearly all the Ferberite into the crusher, causing thousands of specimens to be lost forever.