Calcite (var: Lead-bearing Calcite) ("Plumbocalcite") (RARE locality specimen) (ex Kay Robertson Collection)

Item Description

This is certainly a first for us, as we've never seen a crystal of Lead-bearing Calcite from Concepcion del Oro before. You might have encountered a specimen of Calcite from Tsumeb that was labeled as containing lead, but I can't think of a single instance of something like this coming from Mexico before I saw this specimen. This large miniature / small cabinet is labeled as being "Plumbocalcite", which at one point in time might have been a valid species, but it is now defined as the varietal Lead-bearing Calcite. The specimen features a 4.2 cm, stout, fairly well-formed, sharp, partial rhomb of grey-white Lead-bearing Calcite surrounded by small, sparkling, golden, metallic crystals of Pyrite and no matrix. It presents well as you can see from the photos. I have to believe that this Calcite crystal was analyzed at some point for lead content (which according to mindat can run as high as 4.6% in crystals from Poland), as it is something that one cannot identify visually. A really cool esoteric specimen that could make a great addition to any Calcite collection or a suite of minerals from Mexico. Ex Kay Robertson Collection (#2619). 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.