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Comments: Brown crystals of gjerdingenite-Fe on matrix.
Location: Gjerdingen, Vestbygda, Nordmarka, Jevnaker, Oppland, Norway.
Scale: Picture size 1.2 mm.
© Thomas Witzke / Abraxas-Verlag
Gjerdingenite-Fe: K2[(H2O)2(Fe,Mn)][(Nb,Ti)4(Si4O12)2(O,OH)4]·4(H2O) Ralstonite: NaxMgxAl2-x(F,OH)6·(H2O)
Comments: SEM photomicrograph of gjerdingenite-Fe. The mineral is dusted with tiny crystals of two phases. At high magnification, one of them is seen to form cubes and is probably ralstonite.
Location: Gjerdingselva, Lunner, Oppland, Oslo Region, Norway.
Scale: Crystal length 0.5 mm.
© Canadian Mineralogist