Ulexite Value, Price, and Jewelry Information

By Ra'ike (see also: de:Benutzer:Ra'ike) (Own work) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons

Ulexite

The fibrous material cuts interesting catseye cabochon gems, but they are curios only since they are much too soft and fragile for wear. The eye can be very strong, however. Sometimes ulexite occurs in seams, consisting of tightly packed parallel fibers. These are transparent along their length, and the packed aggregates act like an array of parallel glass fibers, displaying the property of fiber optics. If the material is polished perpendicular to the fiber direction, a piece of ulexite will transmit an image from the bottom of the slab to the top. For this reason the material has been nicknamed TV stone and is popular among mineral enthusiasts.

Ulexite Information

Data Value
Name Ulexite
Stone Sizes Nodules up to several pounds occur. The material is always cut as cabochons; faceting material has never been found.
Formula NaCaB5O9 - SHZO.
Colors Colorless, white.
Fracture Uneven
Hardness 1-2.5
Cleavage Perfect 1 direction
Crystallography Triclinic. Acicular crystals, nodules of fibers, tufts (cottonballs), and veins of parallel fibers.
Refractive Index 1.496-1.519
Birefringence 0.023
Dispersion None.
Luminescence Blue-green in SW, some phosphorescence.
Luminescence Present Yes
Luminescence Type Fluorescent, Phosphorescent, UV-Short
Pleochroism None.
Optics a = 1.496; β = 1.505; γ = 1.519. Biaxial (+), 2V = 78°.
Optic Sign Biaxial +
Luster Vitreous to silky.
Specific Gravity 1.65-1.95
Transparency Transparent to translucent.
Phenomena Chatoyancy.

Optics: a =1.496;β= 1.505; γ=1.519.

Biaxial (+), 2V: 78°.

Occurrence: In playa deposits and dry lakes associated with other borates.

Nevada.

Argentina; Peru; Chile; USSR.

California: world’s major source; also source of TV stone and cabochon material.

Comments: The fibrous material cuts interesting catseye cabochon gems, but they are curios only since they are much too soft and fragile for wear. The eye can be very strong, however. Sometimes ulexite occurs in seams, consisting of tightly packed parallel fibers. These are transparent along their length, and the packed aggregates act like an array of parallel glass fibers, displaying the property of fiber optics. If the material is polished perpendicular to the fiber direction, a piece of ulexite will transmit an image from the bottom of the slab to the top. For this reason the material has been nicknamed TV stone and is popular among mineral enthusiasts.

Name: After the German chemist George L. Ulex, who first presented a correct chemical analysis of the species.

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