Tobermorite on Sphalerite (rare locality specimen) (ex Kay Robertson Collection)

Item Description

A VERY hard to find specimen from the well-known locality at Concepcion del Oro in Mexico. This is only the second specimen of Tobermorite that I've seen from this locality, the first was in the collection of Miguel Romero years ago. Tobermorite is a rare hydrated calcium silicate that gets its name from the first locality where it was found: Tobermory, Isle of Mull, Scotland. Small white radiating "balls" of Tobermorite measuring up to 3 mm are sitting on sharp, lustrous, jet-black crystals of Sphalerite measuring up to 4.3 cm. A stellar piece for anybody who collects rare species or Mexican minerals, as this specimen dates back to what I believe to be an isolated find from the early 1970s, and no more were ever found. Ex Kay Robertson Collection (#7212). Kay is a prominent California collector, who specialized in European classics (see the article in the March-April, 2007 Mineralogical Record and the 50+ page article in the German Magazine "Mineralien Welt" November-December 2017).