Columbite / Tantalite (twin) with Muscovite (ex Kay Robertson Collection)

Item Description

A 1.6 cm, sharp, lustrous, black crystal of most likely Columbite-(Fe) or Tantalite-(Fe) is associated with golden, bladed Musovite from a Linopolis. It's virtually impossible to tell visually which species this is as all of the minerals in the Columbite Group are orthorhombic. A reallly attractive overall specimen considering that good twinned pieces of any species from the Columbite group from Brazil are fairly rare. From the collection of Rolando Gioia (a contributor to new definitive book on Brazilian minerals: "Minerais e Pedras Preciosas do Brasil"). Ex Kay Robertson Collection (#11794). 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).