The photos don't do this piece justice. Though what you see in photo 1 is a great standing piece, on the bottom (or both sides, if you lay it down differently) will reveal a second pocket and a second Herkimer Diamond crystal (hence the piece's nickname).
Spectacular piece - lies in a pyramidal form - with a bright, rainbowy Herkimer Diamond crystal "looking out" onto two faces of the matrix. Real collectors' item, and magical too! Message me with serious interest & Best Offers.
Apparently "old collection" - mines producing this type of material from the Tristate District (OK, MO, KS) were active between 1850 and 1960 - plus you see the tagging on the bottom (3rd picture). Very harmonious display piece, circular, and with wonderful crystallization. In pencil, on the side, is written "sphalerite" - presumably due to some happening on the Galena - prize specimen. We entertain serious Best Offer inquiries, and always provide discounts when possible.