RocksdayCalcite vs Scheelite
How to tell them apart
One of the most common minerals on Earth and the main ingredient of limestone and marble. It breaks into perfect slanted boxes (rhombs) and fizzes in acid.
Photo: Robert M. Lavinsky, CC BY-SA 3.0
Calcium tungstate — heavy, glassy, and glows bright blue-white under shortwave UV.
Photo: Didier Descouens, CC BY-SA 4.0
Quick tests
- Hardness: Scheelite is clearly harder: Mohs 4.5–5 versus 3.
- Acid (vinegar or dilute HCl): Calcite fizzes; Scheelite doesn't.
- Heft: Scheelite feels noticeably heavier for its size (specific gravity 5.9–6.1 vs 2.71).
Key differences
- Calcite is lighter and fizzes in acid.
Side by side
| Property | Calcite | Scheelite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 3 | 4.5–5 |
| Luster | Vitreous | Adamantine to vitreous |
| Streak | White | White |
| Colors | Clear, White, Orange, Yellow, Blue, Green | White, Orange, Yellow, Brown |
| Crystal system | Trigonal | Tetragonal |
| Specific gravity | 2.71 | 5.9–6.1 |
| Formula | CaCO₃ | CaWO₄ |
| Found in | Iceland; Chihuahua, Mexico | Felbertal, Austria; Sangdong, South Korea |
Properties that are the same for both are grayed out.
How to identify calcite
- Fizzes in cold dilute hydrochloric acid (or slowly in vinegar).
- Breaks into rhomb-shaped pieces along three cleavage planes.
- Hardness 3 — a copper coin barely scratches it, a knife easily does.
- Clear pieces show double images of text underneath.
Crystal system: Trigonal
Full Calcite guide →How to identify scheelite
- Surprisingly heavy for a pale mineral.
- Glows bright blue-white in shortwave UV.
- Pyramid-shaped crystals.
Crystal system: Tetragonal
Full Scheelite guide →More comparisons
Could you tell them apart from a blurry close-up?
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