Brown crystal aggregates of this very rare manganese vanadate from the type and only one of two known localities worldwide: Valgraveglia Mine, Reppia, Ne, Graveglia Valley, Genova Province, Liguria, Italy. Ex Vandenbroucke Museum collection specimen, from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Reppiaite
Reppiaite is an IMA-recognized mineral species in the vanadate class, with the chemical formula Mn²⁺₅(VO₄)₂(OH)₄.
It crystallizes in the monoclinic crystal system (space group C2/m).
Key properties: Mohs hardness 3; specific gravity 3.92; Yellow-orange streak; Vitreous luster; optically biaxial.
IMA symbol Rep, IMA status: approved, named in 1991.
A rare mineral, deposited from V–As-bearing hydrothermal solutions in fractures cutting manganiferous cherts.
It is found associated with Hausmannite, tephroite, Mn–Ca carbonates.
The name refers to Reppia, Italy, a village near the locality where the mineral was first found.