mineral
Ulexite
NaCaB5O6(OH)6·5H2O
Hardness: 2.5 on Mohs scale. Color: White, colorless, or grey. Luster: Silky to vitreous. Crystal structure: Triclinic, often forming fibrous masses or 'cotton ball' aggregates. Cleavage: Perfect on {010}. Specific gravity: 1.95 to 1.96.
- Hardness
- 2
- Color
- White, colorless, or grey
- Luster
- Silky to vitreous
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Physical properties
Hardness: 2.5 on Mohs scale. Color: White, colorless, or grey. Luster: Silky to vitreous. Crystal structure: Triclinic, often forming fibrous masses or 'cotton ball' aggregates. Cleavage: Perfect on {010}. Specific gravity: 1.95 to 1.96.
Formation & geological history
Formed as an evaporite mineral in arid regions, particularly in boron-rich playa lakes and salt pans through the evaporation of water over millions of years.
Uses & applications
Used as a major source of boron and borax compounds for the manufacturing of fiberglass, ceramics, and detergents. Also popular among mineral collectors for its unique fiber-optic property.
Geological facts
Ulexite is famously known as 'TV rock' (television rock) because the fibers act as natural fiber optics, projecting an image placed beneath the crystal onto the top surface.
Field identification & locations
Identified by its fibrous appearance, very low specific gravity, and the distinct fiber-optic text-projecting phenomenon. Found in playas of the southwestern United States, Chile, Argentina, and Kazakhstan.
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