Ulexite: Gemstones Information
Ulexite is NaCaB5O6(OH)65H2O and forms masses in colourless parallel fibrous veins along which an image can be carried to the observer,thus from placing the direction of the fibres at right angles to a page of print they will carry a fibre-optic image of the print; the name television stone describes this facility. Ulexite has no other claim to fame but is a member of the triclinic system with one direction of perfect cleavage,hardness 1–2.5, SG upto 1.95. The RI for the alpha, beta and gamma rays is 1,491–1.496, 1.504–1.506, 1.519–1.520, biaxial positive with birefringence 0.023. Ulexite occurs in dry lakes and playa deposits, with other borates. Most material used as television stone comes from borate deposits in California, USA.