Iangreyite, a very rare Ca-Al-phosphate, is a mineral approved in 2010 with IMA 2009-087. It occurs as white crystal aggregtaes on a contrasting matrix. It has been found in only 3 localities worldwide, this one from the type locality: Huber Stock, Krásno, Horní Slavkov, Karlovy Vary Region, Czech Republic. — Photo: David Hospital · CC BY-SA 4.0
Iangreyite
Iangreyite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Ca₂Al₇(PO₄)₂(PO₃OH)₂(OH,F)₁₅·8H₂O.
It crystallizes in the hexagonal crystal system (space group P321).
Key properties: Mohs hardness 3; specific gravity 2.46; White streak; Vitreous, pearly (aggregates) luster; optically uniaxial.
IMA symbol Igy, IMA status: approved, named in 2009.
A weathering product derived from the breakdown of phosphate minerals (e.g. F-rich perhamite, “fluorapatite”) by acidic ground waters derived from the oxidation of sulfide minerals.
It is found associated with Meurigite-Na, plumbogummite, kidwellite, lipscombite, strengite, chalcosiderite, wardite, leucophosphite, wavellite, goethite, barite, quartz.
The mineral was named to honor Dr. Ian Edward Grey (b. 1944), formerly Chief Research Scientist at CSIRO Minerals, Melbourne, Australia, for his contributions to mineralogy.