Ulexite
| Colour | White, Clear |
|---|---|
| Mohs hardness | 2.5 |
| Lustre | Vitreous; silky or satiny in fibrous aggregates |
| Streak | White |
| Crystal system | Triclinic |
| Transparency | Transparent to opaque |
| Cleavage | Perfect on {010} good on {10} poor on {110} |
| Fracture | Uneven |
| Chemical formula | NaCaB 5 O 6 (OH) 6 ·5H 2 O |
| Specific gravity | 1.95–1.96 |
What is Ulexite?
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.
How to identify Ulexite
- Lustre: Vitreous; silky or satiny in fibrous aggregates.
- Hardness: Mohs 2.5 — soft; a knife will scratch it.
- Streak: White.
- Habit: Triclinic crystal system.
Ulexite in different forms
Stones often confused with Ulexite
Frequently asked questions
How hard is Ulexite?
Ulexite is Mohs 2.5 on the hardness scale.
What colour is Ulexite?
Ulexite is typically white, clear (Colorless to white).