Potosiite on Franckeite (very rare material)

Item Description

From the great find of 2004. This specimen is a very attractive, incredibly rare, superb quality, crystallized specimen of Potosiite consisting of an extremely rare, lustrous, striated, tabular blade, measuring 4 mm, sitting on triclinic crystals of the lead, tin, iron, antimony sulfosalt, Franckeite. We have photographed the crystal with a Canon MP-E 65mm macro lens to better illustrate their quality. It must be noted that Potosiite was at one point a valid species, but is now defined as a variety of Franckeite. It does not take away from the great rarity and value of the specimen whatsoever. For those of you who are unaware, the Potosiite crystal on this specimen is EXCEPTIONALLY LARGE for the material. Before these specimens were discovered, some of the largest known crystals of Potosiite were massive, uncrystallized, granules less than 1 mm. in most cases. The crystal on this specimen is NOT a micro, you can clearly see it with the naked eye and it's very distinct. These are undoubtedly some of the LARGEST KNOWN POTOSIITE CRYSTALS IN EXISTENCE. I have been told that the part of the mine that produced these specimens is now mined out and will most likely never produce these impressive specimens again. Originally priced at $250, and the fact that it is nearly impossible to replace in today's market is a big deal.