Green crystals souzalite on Albite; from: Gentil claim, Mendes Pimentel, Minas Gerais, Brazil. Photo and collection Fernando Brederodes — Photo: Fernando Brederodes · CC0
Souzalite
Souzalite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Mg₃Al₄(PO₄)₄(OH)₆·2H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Souzalite structural group.
Key properties: Mohs hardness 5.5–6; specific gravity 3.087; Pale green streak; Vitreous luster; optically biaxial.
IMA symbol Sou, grandfathered status — known before the IMA’s founding, named in 1949.
A rare hydrothermal alteration product of scorzalite in complex zoned granite pegmatites, in sedimentary phosphate nodules, and in a high-pressure kyanite deposit.
It is found associated with Scorzalite.
The mineral was named to honor Dr. Antonio José Alves de Souza (1896–1961), Director, Mineral Survey of Brazil, Rio de Janeiro, Brazil.