Citation: Bjoerling, C O; Westgren, A (1938). Minerals of the Varutrask pegmatite. IX. X-ray studies on triphylite, varulite, and their oxidation products. Geologiska Foereningens i Stockholm Foerhandlingar, 60, pp. 67-72.
Formula: Fe0.35 Mn0.65 O4 P
Chemical name:Manganese(III) iron(III) phosphate(V) (0.65/0.35/1)