Wollastonite Value, Price, and Jewelry Information

Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

Wollastonite

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 Information

Data Value
Name Wollastonite
Colors White, colorless, gray, pale green.
Crystallography Monoclinic and triclinic polytypes. Crystals tabular; massive, cleavable, fibrous, granular.
Refractive Index 1.616-1.653
Luster Vitreous to pearly; silky if fibrous.
Hardness 4.5-5
Fracture Splintery
Specific Gravity 2.8-3.09
Birefringence 0.015
Cleavage Perfect 1 direction
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.
Luminescence Present Yes
Luminescence Type Fluorescent, Phosphorescent, UV-Long, UV-Short
Transparency Transparent to translucent.
Absorption Spectrum Not diagnostic.
Formula

CaSiO3.
Optics

a = 1.616-1.640; β = 1.628-1.650; γ = 1.631-1.653. Biaxial (-), 2V = 38-60°.
Optic Sign Biaxial -

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.

by Joel E. Arem, Ph.D., FGA