Cubanite with Pyrrhotite, Quartz - image 1

Cubanite with Pyrrhotite, Quartz

Unknown Owner

Classic Brazilian specimen with metallic crystals of cubic night and pyrrhotite across the front of an attractive cluster of lustrous colorless gemmy quartz crystals. Siderite is present as well. This is in very good condition. The specimen comes with a previous label and data card, the label from the dealer Larry Conklin. The data card notes and acquisition date of 1972.The Morro Velho mine, also known as AngloGold Ashanti Cuca, located near Nova Lima in the state of Minas Gerais, Brazil, is historically celebrated as one of the oldest and deepest gold mines in the world, as well as a premier locality for exceptionally sharp, highly lustrous crystals of the rare copper iron sulfide mineral cubanite. Geologically, this deposit is classified as an Archean orogenic gold system hosted within the metasedimentary and metavolcanic rocks of the Rio das Velhas greenstone belt, specifically bound to a highly deformed, sulfide-rich iron formation known as the Lapa Seca horizon. Intense regional metamorphism and hydrothermal fluid flow precipitated massive sulfide lenses rich in pyrrhotite, chalcopyrite, and arsenopyrite, where highly specialized localized geochemical conditions allowed orthorhombic cubanite to crystallize not as large masses, but as micrometric inclusions and small, brilliant brass-yellow tabular plates and cyclic twins typically measuring only a few millimeters across within the massive sulfide matrix. Historically, organized underground mining at the site began as early as 1725, but large-scale industrial extraction commenced in 1834 when the Saint John d'el Rey Mining Company acquired the property, initiating a legendary era of deep-level mining where shafts eventually plunged over eight thousand feet beneath the surface. Corporate gold extraction ran continuously through various owners, with the historic underground workings operating non-stop until declining deep reserves and modern economic restructuring closed the main historic underground access points in 2003.Lawrence Conklin was a world-renowned mineral dealer based in New York City, widely regarded as one of the most knowledgeable and sophisticated figures in the history of the mineral trade. Operating from his office on 5th Avenue and later from his home in Connecticut, Conklin specialized in "antique" minerals and specimens with significant historical provenance. He was a meticulous researcher and an elegant writer, often publishing articles that corrected historical errors in mineralogical literature. His career spanned over five decades, during which he handled some of the finest known specimens from classic European and American localities, setting a high standard for aesthetic quality and documentation in the field.