Comparison · Minerals
Calcite vs Fluorite
Calcite and Fluorite are easy to confuse because both are minerals. Fluorite is harder (Mohs 4) than Calcite (Mohs 3), so Fluorite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Calcite and Fluorite
- Fluorite is harder (Mohs 4) than Calcite (Mohs 3), so Fluorite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
- Fluorite feels noticeably heavier for its size (specific gravity 3.2 versus 2.7 for Calcite).
- They overlap in clear, yellow, blue, green, and pink, but Calcite also comes in orange and Fluorite also comes in purple.
- Well-formed crystals give it away: Calcite is trigonal, Fluorite is cubic.
Calcite vs Fluorite properties
| Property | Calcite | Fluorite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 3 | 4 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | transparent | transparent |
| Specific gravity | 2.7 | 3.2 |
| Crystal system | trigonal | cubic |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | Purple, Green, Blue, Yellow, Colorless, Pink |
| Rarity | common | common |
| Typical specimen value | $2–$100+ | $5–$200+ |
Which is more valuable?
Fluorite is usually the more valuable of the two: a typical collector specimen runs about $25 against $15 for Calcite, and premium Fluorite can reach $200 or more.
About Calcite
Calcite is one of the most common minerals on Earth, found in sedimentary, metamorphic, and igneous rocks. It's the primary component of limestone and marble.
About Fluorite
Fluorite is a colorful mineral that often exhibits multiple colors in a single specimen. It's the defining mineral for 4 on the Mohs hardness scale.
Calcite vs Fluorite FAQ
Is Calcite the same as Fluorite?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Fluorite is harder (Mohs 4) than Calcite (Mohs 3), so Fluorite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
How can you tell Calcite from Fluorite?
Fluorite is harder (Mohs 4) than Calcite (Mohs 3), so Fluorite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Fluorite feels noticeably heavier for its size (specific gravity 3.2 versus 2.7 for Calcite). They overlap in clear, yellow, blue, green, and pink, but Calcite also comes in orange and Fluorite also comes in purple.
Which is harder, Calcite or Fluorite?
Fluorite is harder: Mohs 4 against Mohs 3 for Calcite.
Which is more valuable, Calcite or Fluorite?
Fluorite is usually the more valuable of the two: a typical collector specimen runs about $25 against $15 for Calcite, and premium Fluorite can reach $200 or more.
