RocksdayCryolite vs Halite
The quickest way to tell Cryolite from Halite: Cryolite feels noticeably heavier for its size (specific gravity 2.95–3 vs 2.17).
A rare sodium-aluminum fluoride. The only large deposit, at Ivittuut in Greenland, was mined until 1987 as the flux that made aluminum smelting practical.
Photo: Didier Descouens, CC BY-SA 3.0
Natural table salt. It forms thick beds where ancient seas dried up and grows as cubes, sometimes with stair-stepped 'hopper' faces.
Photo: Lech Darski, CC BY-SA 4.0
Quick tests
- Heft: Cryolite feels noticeably heavier for its size (specific gravity 2.95–3 vs 2.17).
Key differences
- Halite tastes salty and dissolves freely.
Side by side
| Property | Cryolite | Halite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 2.5 | 2–2.5 |
| Luster | Vitreous to greasy | Vitreous |
| Streak | White | White |
| Colors | White, Clear, Gray | Clear, White, Pink, Orange |
| Crystal system | Monoclinic | Cubic |
| Specific gravity | 2.95–3 | 2.17 |
| Formula | Na₃AlF₆ | NaCl |
| Found in | Ivittuut, Greenland | Wieliczka, Poland; Khewra, Pakistan |
Properties that are the same for both are grayed out.
How to identify cryolite
- Colorless to white, waxy masses.
- A fingernail barely scratches it.
- Powdered in water, it nearly disappears — its refractive index is close to water's.
Crystal system: Monoclinic
Full Cryolite guide →How to identify halite
- Tastes salty.
- Breaks into cubes.
- Dissolves in water.
- Soft — a fingernail almost scratches it.
Crystal system: Cubic
Full Halite guide →More comparisons
Frequently asked questions
What is the difference between cryolite and halite?
Cryolite is a mineral (Na₃AlF₆) with a Mohs hardness of 2.5 and a vitreous to greasy luster, usually white, colorless or gray. Halite is a mineral (NaCl) with a Mohs hardness of 2–2.5 and a vitreous luster, usually colorless, white, pink or orange.
How can you tell cryolite from halite?
Cryolite feels noticeably heavier for its size (specific gravity 2.95–3 vs 2.17). Halite tastes salty and dissolves freely.
Could you tell them apart from a blurry close-up?
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