A single crystal aggregates of the extremely rare K-Fe oxalate mineral minguzzite from the type and only known locality worrldwide in Elba, Italy (Cape Calamita Mine, Capoliveri, Elba, Livorno Province, Tuscany, Italy). Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Minguzzite
Minguzzite is an IMA-recognized mineral species in the organic mineral class, with the chemical formula K₃Fe³⁺(C₂O₄)₃·3H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Oxalate structural group.
Key properties: specific gravity 2.08; Vitreous luster; optically biaxial.
IMA symbol Mzz, grandfathered status — known before the IMA’s founding, named in 1955.
Rare, in an oxidized gossan formed in a calcareous dolomite.
It is found associated with Humboldtine, “limonite”.
The mineral was named to honor Professor Carlo Minguzzi (1910–1953), Italian mineralogist, University of Pavia, Pavia, Italy.