RocksdayBorax vs Ulexite
How to tell them apart
A sodium borate from dry lake beds. Clear crystals dry out to white powder in normal air.
Photo: Aram Dulyan (User:Aramgutang), Public domain
A fibrous borate whose parallel fibers pipe light like fiber optics.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Key differences
- Ulexite is fibrous and silky.
Side by side
| Property | Borax | Ulexite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 2–2.5 | 2.5 |
| Luster | Vitreous to dull | Silky |
| Streak | White | White |
| Colors | White, Clear | White |
| Crystal system | Monoclinic | Triclinic |
| Specific gravity | 1.7 | 1.95 |
| Formula | Na₂B₄O₇·10H₂O | NaCaB₅O₆(OH)₆·5H₂O |
| Found in | Boron, California; Searles Lake, California | Boron, California; Turkey |
Properties that are the same for both are grayed out.
How to identify borax
- Clear prisms that turn chalky white over time.
- Light and soft.
- Dissolves in water; sweetish-alkaline taste.
Crystal system: Monoclinic
Full Borax guide →How to identify ulexite
- Silky white fibers in parallel bundles.
- Polished slabs show text from underneath on top.
- Light and soft.
Crystal system: Triclinic
Full Ulexite guide →More comparisons
Could you tell them apart from a blurry close-up?
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