- Tazna Mine (Tasna Mine; Tazna-Rosario Mine), Cerro Tazna, Atocha-Quechisla District, Nor Chichas Province, Potosi Department, Bolivia
- Miniature, 4.2 x 3.1 x 3.0 cm
Here is a superb twinned crystal of Ferberite. This piece features the classic, "butterfly" twinning of Ferberite along the (100) face. This piece is a good quailty, sharp, lustrous, aesthetic jet-black twinned crystal.