Potosiite (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 several, extremely rare, lustrous, heavily striated, tabular blades (some are twinned and other are "bent") of measuring up to 9 mm! sitting atop crystallized triclinic crystals of the lead, tin, iron, antimony sulfosalt, Franckeite. Additionally, there are small silvery-grey acicular "strands" of another sulfosalt (most likely Jamesonite or Boulangerite), plus small pale yellow color crystal aggregates of Cervantite, which is very rare in my experience with this material. 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, you can clearly see them with the naked eye and they are 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. Valued at $1450 for rarity, crystal size, associations and the fact that it is nearly impossible to replace.