Found on a museum specimen labeled from the San Jose mine, Brejauba, Minas Gerais, Brazil. Corrected locality is Lavra da Posse, Sao Jose de Berjauba, Conceicao do Mato Dentro County, Link to MinDat.org Location Data.
Name Origin:
Named for Duke University, Duham, North Carolina, USA and for the Mary Duke Biddle Foundation.