Ferberite with rare micro Bismutite

Item Description

The famous Tasna Mine has produced some of the finest Ferberite crystals in the world, including the finest twins of the species ever seen. This piece is from a discovery in 2003 and features attractive, very lustrous, sharp, well-formed, jet black colored bladed crystals measuring up to 3.7 cm sitting atop a thin slab of matrix that is covered by dark golden metallic Marcasite. If you look closely, some of the Marcasite appears to have a greenish tinge, but under magnification, you'll see that there are tiny bright yellow crystals of what is presumably Bismutite, but could be something rarer such as Zaïrite or Russellite. The tiny yellow crystals have not been analyzed, but it's certainly a rare association for the locality, as we can't remember seeing another piece like it from Tasna.   We also found another unknown micro mineral on the piece that is more of a tan-orange hue, and bigger than the yellow crystals.   It's rare to find micro secondary minerals on Ferberite specimens from this mine, so don't pass this one up as this one is nearly 20 years old, and we don't have any more in our inventory like it.