Weloganite: Francon Quarry, Quebec, Canada (0.37). Photo © Joel E. Arem, PhD, FGA. Used with permission.
An overview on Weloganite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Weloganite gems.
| Data | Value |
|---|---|
| Name | Weloganite |
| Formula | Na2Sr3Zr(CO3)6 · 3H2O |
| Colors | White, lemon yellow, amber, colorless. Crystals may be zoned. |
| Fracture | Conchoidal |
| Hardness | 3.5 |
| Cleavage | Perfect |
| Crystallography | Triclinic; crystals pseudo-hexagonal, barrel shaped with heavy striations on prism faces, also grooved due to oscillatory growth. Crystals distinctive, terminated by pedion or pyramids. Also massive. |
| Refractive Index | 1.558-1.648 |
| Birefringence | 0.090 |
| Luminescence | May show triboluminescence |
| Luminescence Present | Yes |
| Absorption Spectrum | Not diagnostic |
| Pleochroism | None |
| Optics | a = 1.558; β = 1.646; γ = 1.648. Biaxial (-). Some stones may appear uniaxial. 2V about 15º. |
| Optic Sign | Biaxial - |
| Luster | Vitreous |
| Specific Gravity | 3.20 |
| Transparency | Transparent to translucent |
| Etymology | For William E. Logan, first director of the Geological Survey of Canada. |
| Occurrence | In an alkalic sill intruding a limestone at St. Michel, Montreal Island, Quebec, Canada. |
Optics: a= 1.558; β= 1.646; γ=1.648.
Name: For William E. Logan, first director of the Geological Survey of Canada.
IGS Become Member