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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
#minerals #mineralogy #mineralcollecting #crystals #Geology #earthsciences #mineral collecting
@Micromineral Fascinating to see how mineral identification evolves with new analytical techniques! The Poudrette quarry specimens are legendary for their complexity - those intergrown manganese oxide phases can be tricky to distinguish without detailed XRD work. Do you know what method was used to separate the birnessite from ranciéite in the mixture?