Lawsonite Value, Price, and Jewelry Information

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

Lawsonite

Lawsonite is extremely rare as a faceted stone, seldom reported and generally unavailable.

Lawsonite Information

Data Value
Name Lawsonite
Colors Colorless, white, gray, blue, pinkish.
Hardness 6-7.5
Fracture Irregular, uneven
Cleavage Perfect in 2 directions
Stone Sizes The maximum likely is 2-3 carats. Gems are pale blue in color.
Formula CaAl­2Si2O7(OH)2 H2O.
Crystallography Orthorhombic. Crystals prismatic; massive, granular.
Refractive Index 1.665-1.686
Birefringence 0.019.
Dispersion High.
Luminescence None.
Luminescence Present No
Absorption Spectrum Not diagnostic.
Pleochroism Blue/yellow-green/colorless or pale brownish yellow/deep blue-green/yellowish.
Optics a = 1.665; β = 1.674-1.675; γ = 1.684-1.686. Biaxial (+), 2V= 84°.
Optic Sign Biaxial +
Luster Vitreous to greasy.
Specific Gravity 3.05-3.12
Transparency Translucent to transaparent.

Optics:  a = 1.665; β= 1.674-1.675; γ= 1.684-1.686.

Biaxial (+), 2V= 84°.

Occurrence: Low-temperature metamorphic rocks; metamorphic schists; glaucophane schists. Santa Clara, Cuba; Italy; Japan: New Caledonia: France; Italy; other locations.

Tiburon Peninsula, California: original material.

Covelo, Mendocino County, California: 2-inch crystals.

Comments: Lawsonite is extremely rare as a faceted stone, seldom reported and generally unavailable.

Name: After Professor A. C. Lawson of the University of California.

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