Comparison · Minerals vs Carbonates
Calcite vs Magnesite
Calcite and Magnesite are easy to confuse. Magnesite is harder (Mohs 4) than Calcite (Mohs 3), so Magnesite 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 Magnesite
- Magnesite is harder (Mohs 4) than Calcite (Mohs 3), so Magnesite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
- Hold a thin edge to the light: Calcite is transparent, Magnesite is translucent.
- They overlap in clear and yellow, but Calcite also comes in orange, blue, green, and pink and Magnesite also comes in gray and brown.
Calcite vs Magnesite properties
| Property | Calcite | Magnesite |
|---|---|---|
| Type | Minerals | Carbonates |
| Mohs hardness | 3 | 4 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | transparent | translucent |
| Specific gravity | 2.7 | 3 |
| Crystal system | trigonal | trigonal |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | White, Gray, Yellowish, Brown, Colorless |
| Rarity | common | common |
| Typical specimen value | $2–$100+ | $3–$150+ |
Which is more valuable?
Magnesite is usually the more valuable of the two: a typical collector specimen runs about $25 against $15 for Calcite, and premium Magnesite can reach $150 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 Magnesite
Magnesite is a magnesium carbonate mineral that forms white to gray crystalline masses and, less commonly, rhombohedral crystals. It is an important source of magnesium and refractory magnesia.
Calcite vs Magnesite FAQ
Is Calcite the same as Magnesite?
No. Calcite is a mineral while Magnesite is a carbonate. Magnesite is harder (Mohs 4) than Calcite (Mohs 3), so Magnesite 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 Magnesite?
Magnesite is harder (Mohs 4) than Calcite (Mohs 3), so Magnesite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Hold a thin edge to the light: Calcite is transparent, Magnesite is translucent. They overlap in clear and yellow, but Calcite also comes in orange, blue, green, and pink and Magnesite also comes in gray and brown.
Which is harder, Calcite or Magnesite?
Magnesite is harder: Mohs 4 against Mohs 3 for Calcite.
Which is more valuable, Calcite or Magnesite?
Magnesite is usually the more valuable of the two: a typical collector specimen runs about $25 against $15 for Calcite, and premium Magnesite can reach $150 or more.
