Xls to 1/6 mm on edge. Via Arnaldo Brunetti (ex Gilles Haineualt). MOB coll. A pair of small, but sharp xls, showing the typical “peatite on the outside, ramikite on the inside” zoning. The background is very dark (altered) rhodochrosite/siderite in curved xls. The other major mineral present is analcime, but there is none in the photo. These xls are close to the resolution limit of my scope. From: Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada. — Photo: Modris Baum · CC0
Peatite-(Y)
Peatite-(Y) is an IMA-recognized mineral species in the phosphate class, with the chemical formula Li₄Na₁₂(Y,Na,Ca,REE)₁₂(PO₄)₁₂(CO₃)₄(F,OH)₈.
It crystallizes in the orthorhombic crystal system (space group P222).
Key properties: Mohs hardness 3; specific gravity 3.62; White streak; Vitreous luster; optically biaxial.
IMA symbol Pti-Y, IMA status: approved, named in 2009.
A late-stage product possibly related to the in situ alteration of the pre-existing mineral assemblage present in the core of a zoned peralkaline pegmatite dike encased in a hornfels xenolith.
It is found associated with Ramikite-(Y), albite, rhodochrosite, siderite, chabazite-Na, synchysite-(Ce), sabinaite.
The mineral was named to honor Cynthia Peat (1925-1999), a former X-ray technician at the Royal Ontario Museum, Toronto, Ontario, Canada.