Birnessite, (Na,Ca,K)0.6(Mn4+,Mn3+)2O4·1.5H2O
Ranciéite, (Ca,Mn2+)0.2(Mn4+,Mn3+)O2·0.6H2O
Originally described as birnessite, new research showed to be a mixture with ranciéite.
Poudrette quarry (Demix quarry; Uni-Mix quarry; Desourdy quarry; Carrière Mont Saint-Hilaire), Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada
FOV = 4.0 mm
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