Franckeite with "Potosiite" (aesthetic specimen)

Item Description

This is one of the rarest sulfosalts in the world. This specimen is a very rich, incredibly rare, superb quality, crystallized specimen of the triclinic lead, tin, iron, antimony sulfosalt Franckeite consisting of somewhat "sword"-shaped crystals oriented into spherical aggregates sitting on matrix! You must understand that about 1% of all the Franckeite specimens from San Jose are actually on matrix. Additionally, there are some minor striated silvery "blades" of the Franckeite variety Potosiite on the reverse side of the piece along with very thin, acicular grey "needles" of another sulfosalt (either Jamesonite, Berthierite or Boulangerite) on the specimen as well. This piece is a great small cabinet specimen for somebody looking to own a rare and highly displayable mineral specimen. This piece is rather aesthetic compared to many other "flat" or two-dimensional pieces of the material that I have seen from San Jose. A good opportunity to acquire something that is rarely offered in the open market for a great price. This species belongs to the only group of minerals that forms in naturally "round" or "cylindrical" shaped crystals. This specimen is over 30 years old and was part of the best find of the material. There were only a handful of good specimens, and well crystallized display pieces like this (especially on matrix) are few and far between. Valued at $900 for the combination of aesthetics, associations and rarity.