Ferberite (excellent quality) (ex Kay Robertson Collection)

Item Description

When it comes to minerals of Colorado, I don't suspect that many people think about tungsten species, but for a time, there was a good amount of tungsten produced in Boulder County. From Nederland to Caribou, and from Sugarloaf to Magnolia there were dozens of localities where tungsten was found. Years ago, the vast majority of this material was labeled as Wolframite, which dates back hundreds of years, and for a long time was a valid species. It is now defined as an intermediary between Hübnerite and Ferberite, but you'll still see the name Wolframite on labels around the world. This piece is almost certainly Ferberite, as virtually everything I've seen analyzed from Boulder County has come back as Ferberite, but what makes the piece special is the fact that it features superb quality, defined, very well-formed CRYSTALS! Most of the Ferberites you'll see on the market from any Boulder County locale are either massive, microscopic or non-distinct, so it's a big deal when you find a piece like this with excellent euhedral crystals which measure up to a full 1.2 cm long. You can see they are notably sharp, lustrous and undamaged for the most part, making this an important and highly desirable example that would fit beautifully into any collection of Colorado minerals or worldwide Ferberites / tungstates. Ex Kay Robertson Collection (#2745). 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.