Carletonite
Carletonite, Poudrette quarry, Mont Saint-Hilaire, Montérégie, Quebec, Canada.
General
CategoryPhyllosilicate
Formula
(repeating unit)		KNa4Ca4(CO3)4Si8O18(F,OH)·(H2O)
IMA symbolCto[1]
Strunz classification9.EB.20
Crystal systemTetragonal
Crystal classDitetragonal dipyramidal (4/mmm)
H–M symbol: (4/m 2/m 2/m)
Space groupP4/mbm
Unit cella = 13.17 Å, c = 16.69 Å; Z = 4
Identification
ColourColourless, light blue, dark blue, or pink
Crystal habitPrismatic crystals, massive
CleavagePerfect on {001}, good on {110}
FractureConchoidal
TenacityBrittle
Mohs scale hardness4 - 4+1⁄2
LustreVitreous
StreakWhite
DiaphaneityTransparent to translucent
Specific gravity2.45
Optical propertiesUniaxial (-)
Refractive indexnω = 1.521 nε = 1.517
Birefringenceδ = 0.004
PleochroismWeak; O = pale blue; E = pale pinkish brown
References[2][3][4][5]

Carletonite is a rare silicate mineral with formula KNa4Ca4(CO3)4Si8O18(F,OH)·(H2O).

It is a phyllosilicate and a member of the apophyllite group. Its tetragonal crystals are a translucent blue, white, colorless or pink with a vitreous to dull lustre. It has a density of 2.45 and a hardness of 4-4.5.

It was discovered by G.Y Chao and named for the school he attended, Carleton University of Ottawa.[6] It was first described in 1969 for an occurrence at Mont Saint-Hilaire, Quebec. The type locality at Mont Saint–Hilaire is the only reported occurrence.[3][4]

It occurs in hornfels and siliceous marble xenoliths within and adjacent to a nepheline syenite intrusion. It occurs in association with quartz, narsarsukite, calcite, fluorite, ancylite, molybdenite, leucosphenite, lorenzenite, galena, albite, pectolite, apophyllite, leifite, microcline and arfvedsonite.[3]

References

  1. ↑ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ↑ Mineralienatlas
  3. 1 2 3 Handbook of Mineralogy
  4. 1 2 Mindat.org
  5. ↑ Webmineral data
  6. ↑ Carletonite is a rare mineral found only in Mt Saint-Hilaire, Quebec, Canada.
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