Coquimbite (rare and good quality) (ex Kay Robertson Collection)

Item Description

An attractive piece of the rare iron sulfate Coquimbite from the San Rafael Swell in Utah. Sharp, well-formed, lustrous, gemmy, brilliant purple colored crystals of Coquimbite measuring up to about 3 mm. This strange mineral is rarely found in specimens larger than a thumbnail or a crust with small crystals. PLEASE NOTE: This mineral is ot stable in high humidity, though this particular specimen has held up for many decades and shows no signs of alteration. Ex Kay Robertson Collection (#2957). 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).