Ruifrancoite , Meurigite-K Locality: Sapucaia Mine, Sapucaia do Norte, Galiléia , Doce valley, Minas Gerais , Southeast Region, Brazil ( Locality at mindat.org ) Brown Ruifrancoite spheres together with yellowish-white hairy Meurigite. Field of view 4 mm. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Ruifrancoite
Ruifrancoite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Ca₂( ,Mn)₂(Fe³⁺,Mn,Mg)₄Be₄(PO₄)₆(OH)₆·4H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Roscherite structural group.
Key properties: Mohs hardness 4.5; specific gravity 2.88; Orange-brown streak; Vitreous luster; optically biaxial.
IMA symbol Rui, IMA status: approved, named in 2005.
A late, vug-filling phase in a zoned LCT-type granitic pegmatite.
It is found associated with Albite, muscovite, cyrilovite, meurigite.
The mineral was named to honor Professor Rui Ribeiro Franco (b. 1916), for his contributions to Brazilian mineralogy and geology, in particular the three-volume Minerals do Brazil (1972).