Properties
| Category | Nesoborates |
|---|---|
| Formula | NaCaB5O6(OH)6·5H2O |
| Crystal system | Triclinic |
| Color | Colorless to white |
| Crystal habit | Acicular to fibrous |
| Cleavage | Perfect on {010} good on {110} poor on {110} |
| Fracture | Uneven |
| Tenacity | Brittle |
| Mohs scale hardness | 2.5 |
| Luster | Vitreous; silky or satiny in fibrous aggregates |
| Streak | White |
| Diaphaneity | Transparent to opaque |
| Specific gravity | 1.95–1.96 |
From the Wikipedia article
Ulexite, sometimes called TV rock or TV stone due to its unusual optical properties, is a hydrous borate hydroxide of sodium and calcium with the chemical formula NaCaB5O6(OH)6·5H2O. The mineral occurs as silky white rounded crystalline masses or in parallel fibers. Ulexite was named for the German chemist Georg Ludwig Ulex (1811–1883), who first discovered it.
Source
Source record: crystal-compendium/ulexite/minerals.json. Fetched from English Wikipedia by the operator 2 October 2026.
https://en.wikipedia.org/wiki/Ulexite — revision id 1360522395. Text and properties from Wikipedia, licensed CC BY-SA 4.0.