Columbite / Tantalite on Muscovite (ex Rolando Gioia Collection)

Item Description

A 1.1 cm, sharp, lustrous, black crystal of most likely Columbite-(Fe) or Tantalite-(Fe) is associated with a secondary partial crystal sitting on a mass of compacted silvery Musovite from an undisclosed locality in Minas Gerais. It's virtually impossible to tell visually which species this is as all of the minerals in the Columbite Group are orthorhombic and they form, but since the second crystal is not complete, it could be sampled and easily analyzed to confirm its identity. A reallly attractive overall specimen considering that matrix pieces of any species from the Columbite group are quite rare. From the collection of Rolando Gioia (a contributor to new definitive book on Brazilian minerals: "Minerais e Pedras Preciosas do Brasil"). From the collection of Rolando Gioia (a contributor to new definitive book on Brazilian minerals: "Minerais e Pedras Preciosas do Brasil").