Lawsonite is extremely rare as a faceted stone, seldom reported and generally unavailable.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Crystallography||Orthorhombic. Crystals prismatic; massive, granular.|
|Colors||Colorless, white, gray, blue, pinkish.|
|Luster||Vitreous to greasy.|
|Cleavage||Perfect in 2 directions.|
|Stone Sizes||The maximum likely is 2-3 carats. Gems are pale blue in color.|
|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°.
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.