Poppiite
Poppiite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₂V³⁺V³⁺₂(Si₂O₇)(SiO₄)(OH,O)₂·H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Pumpellyite structural group.
Key properties: specific gravity 3.36; Greenish white streak; Vitreous luster; optically biaxial.
IMA symbol Pop, IMA status: approved, named in 2005.
Found in metamorphosed sedimentary manganese deposits.
It is found associated with Roscoelite, ganophyllite, manganaxinite, goldmanite, calcite (Italy); manganiferous calcite, goldmanite, V-bearing axinite-(Mn), rhodonite.
The mineral was named to honor Luciano Poppi, Professor of Mineralogy, Modena and Reggio Emilia University, Italy, for his generous and fruitful efforts devoted to mineral science.