Citation: Dai, Y. S.; Harlow, G. E.; McGhie, A. R. (1993). Poldervaartite, Ca(Ca0.5Mn0.5)(SiO3OH)(OH), a new acid nesosilicate from the Kalahari manganese field, South Africa: Crystal structure and description. American Mineralogist, 78, pp. 1082-1087.