Falsterite
A rare complex pegmatite phosphate related to ferraioloite.
Intro adapted from Wikipedia (CC BY-SA).
Falsterite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Ca₂MgMn²⁺₂Fe²⁺₂Fe³⁺₂Zn₄(PO₄)₈(OH)₄(H₂O)₁₄.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: Mohs hardness 2; specific gravity 2.78; Pale greenish blue streak; Vitreous luster; optically biaxial.
IMA symbol Fls, IMA status: approved, named in 2011.
Formed as the result of secondary alteration of primary triphylite and associated sphalerite in the core-margin of a well-zoned beryl-phosphate granitic pegmatite.
It is found associated with Messelite, mitridatite, phosphophyllite, quartz, schoonerite, siderite, smithsonite, vivianite (Palermo No 1); almandine, fairfieldite, muscovite, quartz.
The mineral was named to honor Alexander U. Falster (b. 1952), a Scientific Research Technologist, Department of Earth and Environmental Science, University of New Orleans, Louisiana, USA.