Pyrolusite (choice crystals!) (ex Kay Robertson Collection)

Item Description

A FINE quality specimens of very well-formed, sharp, silvery-black colored tetrahedral "cockscomb"-esque groups Pyrolusite measuring up to 5 mm from near Siegen, Germany. The label accompanying the piece states that it's from a locality called "Herdorf", but I can't find a listing for this locality for Pyrolusite. These are excellent crystals of a species that is well-known worldwide, but rarely found is such choice examples. Valued at $850. Ex Kay Robertson Collection (#2370). 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).