Franckeite, Zinkenite
San Jose Mine, Oruro City, Cercado Province, Oruro Department, Bolivia
Miniature, 3.7 x 2.5 x 2.2 cm
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 forming the shape of a flower. They are associated with very rare silvery, prismatic "needles" of Zinkenite, which is a very uncommon association from any locality. Franckeite 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 are few and far between. Ex. Brian Kosnar.