By Ra'ike (see also: de:Benutzer:Ra'ike) (Own work) [GFDL or CC-BY-SA-3.0], via Wikimedia Commons
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 Value
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
Ulexite Information
| Data | Value |
| Name | Ulexite |
| Crystallography | Triclinic. Acicular crystals, nodules of fibers, tufts (cottonballs). and veins of parallel fibers. |
| Colors | Colorless, white. |
| Luster | Vitreous to silky. |
| Hardness | L-2.5. |
| Density | 1.65-1.95. |
| Birefringence | 0.023. |
| Cleavage | Perfect 1 direction. Brittle. |
| Stone Sizes | Nodules up to several pounds occur. The material is always cut as cabochons; faceting material has never been found. |
| Luminescence | Blue-green in SW, some phosphorescence. |
| Formula | NaCaB5O9 - SHZO. |
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.
