Comparison · Minerals vs Silicate Minerals
Calcite vs Natrolite
Calcite and Natrolite are easy to confuse. Natrolite is harder (Mohs 5.5) than Calcite (Mohs 3), so Natrolite 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 Natrolite
- Natrolite is harder (Mohs 5.5) than Calcite (Mohs 3), so Natrolite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
- They overlap in clear, yellow, and pink, but Calcite also comes in orange, blue, and green and Natrolite also comes in gray.
- Well-formed crystals give it away: Calcite is trigonal, Natrolite is orthorhombic.
Calcite vs Natrolite properties
| Property | Calcite | Natrolite |
|---|---|---|
| Type | Minerals | Silicate Minerals |
| Mohs hardness | 3 | 5.5 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | transparent | transparent |
| Specific gravity | 2.7 | 2.25 |
| Crystal system | trigonal | orthorhombic |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | Colorless, White, Pink, Yellow, Gray |
| Rarity | common | uncommon |
| Typical specimen value | $2–$100+ | $8–$250+ |
Which is more valuable?
Natrolite is usually the more valuable of the two: a typical collector specimen runs about $45 against $15 for Calcite, and premium Natrolite can reach $250 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 Natrolite
Natrolite is a sodium-rich zeolite mineral that forms delicate, slender prismatic crystals, often gathered into radiating sprays. It typically occurs in cavities of basalt and is valued by collectors for its needle-like sprays.
Calcite vs Natrolite FAQ
Is Calcite the same as Natrolite?
No. Calcite is a mineral while Natrolite is a silicate mineral. Natrolite is harder (Mohs 5.5) than Calcite (Mohs 3), so Natrolite 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 Natrolite?
Natrolite is harder (Mohs 5.5) than Calcite (Mohs 3), so Natrolite will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. They overlap in clear, yellow, and pink, but Calcite also comes in orange, blue, and green and Natrolite also comes in gray. Well-formed crystals give it away: Calcite is trigonal, Natrolite is orthorhombic.
Which is harder, Calcite or Natrolite?
Natrolite is harder: Mohs 5.5 against Mohs 3 for Calcite.
Which is more valuable, Calcite or Natrolite?
Natrolite is usually the more valuable of the two: a typical collector specimen runs about $45 against $15 for Calcite, and premium Natrolite can reach $250 or more.
