Gaylussite Value, Price, and Jewelry Information

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

Gaylussite

This mineral is very hard to cut because of extreme softness and cleavage. Gaylussite dries out slowly in air and the surfaces may turn white. Stones in collections are therefore best stored in sealed containers to prevent dehydration. Gaylussite is seen only in very comprehensive collections, and relatively few stones have been cut. Transparent crystals are not terribly rare, but faceted gems are relatively uninteresting.

Gaylussite Information

Data Value
Name Gaylussite
Colors Colorless, white, grayish, yellowish.
Crystallography Monoclinic. Crystals elongated, flattened, and wedge-shaped.
Refractive Index 1.445-1.522
Luster Vitreous.
Hardness 2.5 - 3
Fracture Conchoidal
Specific Gravity 1.995
Birefringence 0.077
Cleavage Perfect 1 direction
Stone Sizes Crystals from Searles Lake have been found up to 2 inches long. Gems cut from such crystals could be up to about 20-30 carats.
Luminescence Weak cream white in SW (Nevada). May be triboluminescent.
Luminescence Present Yes
Luminescence Type Fluorescent, UV-Short
Transparency Transparent to translucent.
Absorption Spectrum Not diagnostic.
Formula

Na2Ca(CO3) ·5H2O
Pleochroism

None.
Optics

a = 1.445; β = 1.516; γ = 1.522. Biaxial (-), 2V = 34°.
Optic Sign Biaxial -

Optics:  a = 1.445;β= 1.516; γ= 1.522.

Biaxial (-), 2V = 34°

Occurrence: In alkaline lakes or evaporite deposits rich in borax.

California: Searles Lake, Owens Lake, China Lake. Borax Lake.

Wyoming; Nevada.

Mongolia, China.

Venezuela: in clay beds.

Kenya: in transparent crystals, from Lake Amboseli.

Comments: This mineral is very hard to cut because of extreme softness and cleavage. Gaylussite dries out slowly in air and the surfaces may turn white. Stones in collections are therefore best stored in sealed containers to prevent dehydration. Gaylussite is seen only in very comprehensive collections, and relatively few stones have been cut. Transparent crystals are not terribly rare, but faceted gems are relatively uninteresting.

Name: After the eminent French chemist, Professor L. J. Gay-Lussac.

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