RocksdayBastnäsite vs Calcite
The quickest way to tell Bastnäsite from Calcite: Bastnäsite feels noticeably heavier for its size (specific gravity 4.9–5.2 vs 2.71).
A rare-earth fluorocarbonate and one of the main ores of cerium and its neighbors. It is heavy and fizzes in acid.
Photo: Kouame, CC BY-SA 3.0
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
Quick tests
- Heft: Bastnäsite feels noticeably heavier for its size (specific gravity 4.9–5.2 vs 2.71).
Key differences
- Calcite is much lighter and softer.
Side by side
| Property | Bastnäsite | Calcite |
|---|---|---|
| Type | Mineral | Mineral |
| Mohs hardness | 4–4.5 | 3 |
| Luster | Vitreous to greasy | Vitreous |
| Streak | White | White |
| Colors | Yellow, Brown, Red | Clear, White, Orange, Yellow, Blue, Green |
| Crystal system | Hexagonal | Trigonal |
| Specific gravity | 4.9–5.2 | 2.71 |
| Formula | (Ce,La)(CO₃)F | CaCO₃ |
| Found in | Mountain Pass, California; Bayan Obo, China | Iceland; Chihuahua, Mexico |
Properties that are the same for both are grayed out.
How to identify bastnäsite
- Yellow, brown or reddish masses or hexagonal crystals.
- Heavy for a non-metallic mineral.
- Fizzes in acid. Hardness about 4–4.5.
Crystal system: Hexagonal
Full Bastnäsite guide →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 →More comparisons
Frequently asked questions
What is the difference between bastnäsite and calcite?
Bastnäsite is a mineral with a Mohs hardness of 4–4.5 and a vitreous to greasy luster, usually yellow, brown or red. Calcite is a mineral (CaCO₃) with a Mohs hardness of 3 and a vitreous luster, usually colorless, white, orange, yellow, blue or green.
How can you tell bastnäsite from calcite?
Bastnäsite feels noticeably heavier for its size (specific gravity 4.9–5.2 vs 2.71). Calcite is much lighter and softer.
Could you tell them apart from a blurry close-up?
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