Horváthite-(Y)

horvathite-(Y)

dawsonite

catapleiite

genthelvite

Images

Formula: NaY(CO3)F2
Anhydrous carbonate, yttrium-bearing mineral
Crystal system: Orthorhombic
Specific gravity: 3.58 measured, 3.46 calculated
Hardness: 4
Streak: White
Colour: Colourless to pale beige
Luminescence: Does not fluoresce under UV
Environments

Pegmatites

Localities

The type locality is the Poudrette quarry, Mont Saint-Hilaire, La Vallée-du-Richelieu RCM, Montérégie, Québec, Canada. Mont Saint-Hilaire is an alkaline intusive complex. Horváthite-(Y) is a very rare mineral; specimens were collected from a large pegmatite dike in the nepheline syenite intrusive unit. The portion of the pegmatite in which horváthite-(Y) was found is quite altered; many of the minerals with horváthite-(Y) inclusions are etched and corroded. Horváthite-(Y) is associated with microcline, aegirine, dawsonite, rhodochrosite, sodalite, natrolite, albite, serandite, siderite, tainiolite, catapleiite, astrophyllite, genthelvite, and a franconite group mineral. In another part of the same pegmatite dike, horváthite-(Y) is also associated with adamsite-(Y) (previously UK96), an alteration product of adamsite-(Y), sphalerite, rhodochrosite and microcline.
Horváthite-(Y) has two distinct habits: (1) stacks of plates, measuring approximately 1 X 1 X 0.25 mm3, and (2) blocky aggregates of radiating crysals 1 to 5 mm across wilh individual, striated prismatic crystals up to 1 mm long. The aggregates are commonly "wagon-wheel" or cylindrical in habit (CM 35.3.743-749).
Horváthite-(Y) from the Poudrette Quarry - Image

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