Brown crystallized zanazziite across the matrix (5.0 × 2.5 × 2.5 cm). Found from Jenipapo, Itinga, Minas Gerais, Brazil. — Photo: Ivar Leidus · CC BY-SA 4.0
Zanazziite
A magnesium-beryllium phosphate of the roscherite group — barrel-shaped crystals to 4 mm.
Intro adapted from Wikipedia (CC BY-SA).
Zanazziite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Ca₂Be₄Mg₅(PO₄)₆(OH)₄·6H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Roscherite structural group.
Key properties: Mohs hardness 5; specific gravity 2.76; White streak; Vitreous to pearly on cleavages luster; refractive index 1.717; optically biaxial.
IMA symbol Zan, IMA status: approved, named in 1986.
Found in a simply zoned granite pegmatite with other phosphates (Lavra da Ilha pegmatite, Brazil).
It is found associated with Quartz, albite, muscovite, wardite, eosphorite, whiteite, apatite, pyrite, manganese oxides (Lavra da Ilha pegmatite, Brazil); fluorapatite.
The mineral was named to honor Dr. Pier Francesco Zanazzi (1939–), Professor of Mineralogy, University of Perugia, Perugia, Italy, for his structural studies of many minerals, including this one.