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.
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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