RocksdayCelestine vs Strontianite
How to tell them apart
Strontium sulfate, best known for pale sky-blue crystals filling geodes from Madagascar.
Photo: Ivar Leidus, CC BY-SA 4.0
Strontium carbonate forming white tufts and needles; it colors a flame crimson.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Quick tests
- Acid (vinegar or dilute HCl): Strontianite fizzes; Celestine doesn't.
Key differences
- Celestine doesn't fizz.
Side by side
| Property | Celestine | Strontianite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 3–3.5 | 3.5 |
| Luster | Vitreous to pearly | Vitreous to resinous |
| Streak | White | White |
| Colors | Blue, White, Clear | White, Gray, Yellow, Green |
| Crystal system | Orthorhombic | Orthorhombic |
| Specific gravity | 3.95–3.97 | 3.74–3.78 |
| Formula | SrSO₄ | SrCO₃ |
| Found in | Sakoany, Madagascar; Put-in-Bay, Ohio | Strontian, Scotland; Münsterland, Germany |
Properties that are the same for both are grayed out.
How to identify celestine
- Pale sky blue, sometimes white.
- Bladed or tabular crystals.
- Heavy for a pale mineral.
- Turns a flame crimson red.
Crystal system: Orthorhombic
Full Celestine guide →How to identify strontianite
- White to pale needles in tufts.
- Fizzes in acid.
- Turns a flame red.
Crystal system: Orthorhombic
Full Strontianite guide →More comparisons
Could you tell them apart from a blurry close-up?
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