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CategoryCarbonate mineral
(repeating unit)
IMA symbolWlg[1]
Strunz classification5.CC.05
Dana classification15.3.4.4
Crystal systemTriclinic
Crystal classPedial (1)
(same H-M symbol)
Space groupP1
Unit cella = 8.966 Å, b = 8.98 Å
c = 6.73 Å; α = 102.72°
β = 116.65°, γ = 60.06°; Z = 1
Formula mass814.16 g/mol
ColorYellow, pale yellow, amber, tan, white
Crystal habitRoughly hexagonal, tapering crystals, pseudorhombohedral
TwinningAbout [103] repeated at 120 degrees
CleavagePerfect on pseudo {0001}
Mohs scale hardness3+12
Specific gravity3.20 - 3.22
Optical propertiesBiaxial (-)
Refractive indexnα = 1.558 nβ = 1.646 nγ = 1.640
Birefringenceδ = 0.082
2V angleMeasured: 15°
Other characteristicsPyroelectric. triboluminescent.

Weloganite is a rare carbonate mineral with formula: Na2(Sr,Ca)3Zr(CO3)6·3H2O. It was discovered by Canadian government mineralogist Ann P. Sabina in 1967 and named for Canadian geologist Sir William Edmond Logan (1798–1875). It was first discovered in Francon Quarry,[7] Montreal, Quebec, Canada and has only been reported from a few localities worldwide.


It is usually white, lemon yellow, or amber in color, and can be translucent. It crystallizes in the triclinic system and shows pseudo-hexagonal crystal forms due to twinning. The width of the crystals typically undulates down the length, forming crystals that widen in the middle or flare out at the end. Crystals are affected by light and can develop a white alteration coating over time. Weloganite is triboluminescent, producing blue light.


It occurs in an igneous carbonatite sill in Montreal, Quebec, Canada in the Francon Quarry where it was first discovered. It also occurs in the Mont Saint-Hilaire district. Associated minerals include strontianite, dawsonite and calcite. It has also been reported from the Pilansberg Complex of the western Bushveld Igneous Complex in South Africa.[5]

See also[edit]


  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. ^ Sabina, A., 'Weloganite, a new strontium zirconium carbonate from Montreal Island, Canada', The Canadian Mineralogist, 9, pp.468-477, 1968.
  3. ^ Grice, J. D. and Perrault G., 'The crystal structure of triclinic weloganite', The Canadian Mineralogist, 13, pp.209-216, 1975.
  4. ^ Handbook of Mineralogy
  5. ^ a b Mindat
  6. ^ Webmineral
  7. ^ Ramik, Robert A. (August 1983). "Viitaniemiite from the Francon Quarry, Montreal, Quebec on GeoScienceWorld". The Canadian Mineralogist. 21 (3): 499–502.

External links[edit]