Mccrillisite
Mccrillisite is an IMA-recognized mineral species in the phosphate class, with the chemical formula NaCs(Be,Li)Zr₂(PO₄)₄·1-2H₂O.
Key properties: Mohs hardness 4–4.5; specific gravity 3.125; White streak; Vitreous luster; optically uniaxial.
IMA symbol Mcr, IMA status: approved, named in 1991.
A rare product of late-stage hydrothermal alteration of primary zirconium-bearing minerals, in a complex granite pegmatite.
It is found associated with Zircon, kosnarite, roscherite, moraesite, eosphorite, löllingite, uraninite, albite, quartz, manganoan almandine, muscovite, siderite, fluorapatite, elbaite.
The mineral was named to honor the McCrillis family, principally Dean (1931–1989) and his son, Phillip, pegmatite miners from Oxford Co., Maine, USA.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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