- Tazna Mine (Tasna Mine; Tazna-Rosario Mine), Cerro Tazna, Atocha-Quechisla District, Nor Chichas Province, Potosi Department, Bolivia
- Miniature, 4.0 x 3.8 x 3.2 cm
A superb Ferberite from perhaps the premier locality for the twinned crystals. This piece features the classic, "butterfly" twinning of Ferberite along the a (100) face. It is a beautiful, sharp, highly lustrous, aesthetic jet-black twinned crystal with razor sharp, smooth reflective faces. It has an attractive thick blocky form, and is a wonderful miniature. Twinned 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. These twins are definitely the most highly sought after crystal habit from this locality. Mined in 2003.