@article{article4f544725, title = {Melcherite, trigonal Ba2Na2Mg[Nb6O19].6H2O, the second natural hexaniobate, from Cajati, São Paulo, Brazil: description and crystal structure}, author = {Andrade, Marcelo Barbosa de and Atencio, Daniel and Menezes Filho, Luiz Alberto Dias and Spratt, John}, year = {2018}, doi = {10.1180/minmag.2017.081.026}, journal = {Mineralogical Magazine} }