Potosiite (very rare LARGE crystals) on Franckeite

Item Description

From the great find of 2004. This specimen is a very attractive, incredibly rare, superb quality, crystallized specimen of Potosiite consisting of a few extremely rare, heavily striated, silvery colored tabular blades measuring up to 1.3 cm (!!) sitting atop crystallized, grey, triclinic crystals of the lead, tin, iron, antimony sulfosalt, Franckeite. Some of the Potosiites actually show beautifuly "V"-shaped or "butterfly" twinning, while other crystals look slightly "curved" or "bent". I can see a small "tuft" of an unknown acicular sulfosalt, most likely Jamesonite or Boulangerite. It must be noted that Potosiite was at one point a valied 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 crystals on this specimen are EXCEPTIONALLY LARGE for the material. Before these new specimens were discovered, some of the largest known crystals of Potosiite were massive, uncrystallized, granules less than 1 mm in most cases. The crystals on this specimen are NOT micros; they are distinct, and you can clearly see them with the naked eye 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. This piece is valued at $2,800 simply for the fact that it has such a large crystal of Potosiite on there. Anything over 1 cm is quite large, and up to 1.5 cm is considered extraordinary for the material.