Chalcedony pseudomorph after Calcite (ex Kay Robertson Collection)

Item Description

An unusual and rarely seen pseudomorph of Chalcedony which as completely replaced a single "dog tooth"-shaped crystal of scalenohedral Calcite. A somewhat honeycombed pattern of blue and white can be seen on the exterior of the specimen, and there is even a small area which is open and show the hollow / negative space inside the piece. Ex Kay Robertson Collection (#9045). 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 Velt" November-December 2017). A strange and worthwhile rarity from California!