Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons
Wilkeite
An overview on Wilkeite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Wilkeite gems.
Wilkeite Information
| Data | Value |
|---|---|
| Name | Wilkeite |
| Is a Variety of | Apatite |
| Crystallography | Hexagonal. Crystals rounded; granular; massive. |
| Refractive Index | 1.636-1.650 |
| Colors | Pale pinkish, yellowish, rose red. |
| Hardness | 5 |
| Birefringence | 0.010 |
| Cleavage | Imperfect |
| Stone Sizes | Cuttable crystal fragments have been encountered, but I know of no faceted gems. |
| Luminescence | None reported. |
| Luminescence Present | No |
| Absorption Spectrum | Not diagnostic. |
| Formula | Ca5(SiO4PO4SO4)3(O,OH,F). |
| Optics | o = 1.640-1.650; e = 1.636-1.646. Uniaxial (-). |
| Optic Sign | Uniaxial - |
| Luster | Vitreous to resinous. |
| Specific Gravity | 3.12-3.23 |
| Transparency | Transparent to translucent. |
Apatite Group.
Occurrence: In metamorphosed marbles.
Kyshtym, Urals, USSR; Laacher See, Germany.
Crestmore, California in marble.
Comments: Wilkeite is a rare silicate—sulfate apatite that has not been encountered as faceted gems; however. I have seen cuttable crystals that would yield stones in the 1-5 carat range. These would be extremely rare stones.
Name: After R. M. Wilke, mineral collector and dealer in Palo Alto, California.
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