Columbite

specimen number:
2322008

location:
Sapo Mine, Ferruginha, Conselheiro Pena, Minas Gerais, Brazil

description:
Very good matrix example for the species, a lustrous black terminated crystal 3.5 cm in height coming off of a muscovite and albite crystal matrix. This is in very good condition.

The Sapo Mine, located near Conselheiro Pena in the Doce River valley of Minas Gerais, Brazil, is a celebrated pegmatite mining operation worked primarily for gemstones and mineral specimens. Geologically, the deposit consists of complex granitic pegmatites intruding into regional metamorphic rocks, heavily weathered near the surface into soft kaolin pockets that allow for manual extraction. Historically developed during the latter half of the twentieth century with significant modern specimen discoveries continuing into the 2000s, the mine has gained worldwide fame among collectors for yielding exceptional, undamaged crystals of hydroxylapatite, tourmaline, and associated accessory species.

The columbite series comprises critical niobium-tantalum oxide minerals, specifically columbite-(Fe), columbite-(Mn), and columbite-(Mg), which form solid solution series in granitic pegmatites. These dark, submetallic to black orthorhombic crystals are major ore minerals for the high-tech and aerospace industries, and they frequently occur alongside accessory phases like tantalite, beryl, and lithium minerals within zoned pegmatite fields.

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