Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons
Interesting cabochons have been cut from wollastonite, especially from the fibrous material (which yields catseye stones) and the reddish material from Lake Superior’s lsle Royale. Wollastonite is strictly a curiosity and as a mineral is not especially rare. It resembles other white fibrous minerals, however, and is sometimes difficult to identify without using X—ray techniques. Facetable wollastonite is exceedingly rare, the material from Asbestos, Quebec (Jeffrey Mine) being singularly notable. Such gems are, moreover, extremely difficult to cut because of the cleavage and fibrosity of the mineral.
Wollastonite Value
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Wollastonite Information
| Data | Value |
| Name | Wollastonite |
| Crystallography | Triclinic. Crystals tabular; massive, cleavable, fibrous, granular. |
| Colors | White, colorless, gray, pale green. |
| Luster | Vitreous to pearly; silky if fibrous. |
| Hardness | 4.5-5 |
| Density | 2.8—3.09 |
| Birefringence | 0.015 |
| Cleavage | Perfect 1 direction. Fracture splintery. Brittle. |
| Stone Sizes | Cabochons up to several inches in length can be cut from fibrous and massive material. Very few faceted gems have been reported. USNM: 1.22. National Museums of Canada (Ottawa, Ontario): 4.05. Private Collection: 0.75 (Asbestos, Quebec), |
| Luminescence | Fluoresces blue-green and phosphoresces yellow in SW, same in LW, from California, Alaska, and Pennsylvania. Material from Asbestos, Quebec, Canada, is nonluminescent. |
| Spectral | Not diagnostic |
| Formula | CaSiO3. |
Optics: a =1.616-1.640; β= 1.628-1.650; γ: 1.631-1.653.
Biaxial (-), 2V: 38-60°.
Shadow edge in refractometer about 1.63.
Occurrence: Metamorphosed limestones and alkalic igneous rocks.
California (various localities); Willsboro, New York; Alaska: Pennsylvania; New Mexico.
Ontario and Quebec, Canada; Chiapas, Mexico; Norway:
Italy; Rumania; Finland.
Isle Royale, Lake Superior: compact, pale red material, good for cutting cabochons.
Comments: Interesting cabochons have been cut from wollastonite, especially from the fibrous material (which yields catseye stones) and the reddish material from Lake Superior’s lsle Royale. Wollastonite is strictly a curiosity and as a mineral is not especially rare. It resembles other white fibrous minerals, however, and is sometimes difficult to identify without using X—ray techniques. Facetable wollastonite is exceedingly rare, the material from Asbestos, Quebec (Jeffrey Mine) being singularly notable. Such gems are, moreover, extremely difficult to cut because of the cleavage and fibrosity of the mineral.
Name: After W. H. Wollaston, British mineralogist and chemist.
