- Tazna Mine (Tasna Mine; Tazna-Rosario Mine), Cerro Tazna, Atocha-Quechisla District, Nor Chichas Province, Potosi Department, Bolivia
- Miniature, 5.0 x 3.8 x 3.3 cm
A very unusual and completely unique, stacked/layered, multi-twinned crystal of Ferberite from the renowned Tazna mine in southern Bolivia. The piece was mined at the beginning of 2008, which is encouraging because I have seen very little in the way of Ferberites from this mine in recent years. This piece features the classic, "butterfly" twinning of Ferberite along the a (100) face. It is a superb, sharp, lustrous, jet-black twinned crystal with several smaller secondary crystals running parallel to the main twinned crystal. It has an attractive form, and is a wonderful example of how bizarre the twins from this mine can get. 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.