Volborthite with Chrysocolla (ex Kay Robertson Collection)

Item Description

A classic example of Volborthite from the Monument No. 1 Mine in Arizona. This mine is best known for its Volborthite specimens which have a characteristic electric yellow-green color, and platy, sometimes "rosette"-like crystal formations. Typically species with this kind of color can attribute it to the presence of Uranium, but that is not the case with Volborthite. This piece has a fair amount of crystals which are associated with pale blue Chrysocolla (originally labeled as Allophane) and minor black "specks" of what could be Montroseite or Roscoelite(?). A good representative specimen of this uncommon hydrated copper hydroxyl vanadate. Ex Kay Robertson Collection (#4210). 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).