Tetrahedrite with Sphalerite and Pyrite (ex Kay Robertson Collection)

Item Description

A nice representative specimen of the old-time Casapalca material that came out in the early 1970s. Although this piece is not what one would refer to as a "killer", back in the day it was a big deal and important specimen as crystals of Tetrahedrite this size were incredibly rare to find on the market from any locality. The display side of the specimen is filled with sharp, grey-black tetrahedral crystals of Tetrahedrite measuring up to 1.7 cm, while the underside features massive associated greenish-black Sphalerite and metallic golden Pyrite. I can see a small amount of associated silvery-grey Galena on one edge as well. There are some dings to the Tetrahedrites, so it's not a pristine specimen, but it's a great "time capsule" specimen that shows what was coming out of the mine at the time. Ex Kay Robertson Collection (#1163). Kay was a prominent California collector, who specialized in European classics. She nearly lived 100 years from April 1920 - March 2020. See the article in the March-April, 2007 Mineralogical Record ( https://www.mineralogicalrecord.com/pdfs/Kay%20Robertson%20Collection.pdf ), and the 50+ page article in the German Magazine "Mineralien Welt" November-December 2017.