(Fe,Mn)(Ta,Nb)₂O₆

This sample of tapiolite is displayed in the Smithsonian Museum of Natural History. Tapiolite is an oxide mineral of niobium, manganese, tantalum and iron. It has the composition (Fe,Mn)(Ta,Nb)₂O₆. This sample is about 3 cm and is from Alto do Giz mine, Equador, Rio Grande do North, Brazil.