Comparison · Minerals
Calcite vs Tourmaline
Calcite and Tourmaline are easy to confuse because both are minerals. Tourmaline is harder (Mohs 7–7.5) than Calcite (Mohs 3), so Tourmaline 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 Tourmaline
- Tourmaline is harder (Mohs 7–7.5) than Calcite (Mohs 3), so Tourmaline will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not.
- Streak color differs: Calcite leaves a white streak on unglazed porcelain, Tourmaline leaves white (colorless).
- Hold a thin edge to the light: Calcite is transparent, Tourmaline is Transparent to opaque.
- They overlap in blue, green, and pink, but Calcite also comes in clear, yellow, and orange and Tourmaline also comes in black and multicolored.
- Well-formed crystals give it away: Calcite is trigonal, Tourmaline is Trigonal.
Calcite vs Tourmaline properties
| Property | Calcite | Tourmaline |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 3 | 7–7.5 |
| Luster | vitreous | Vitreous |
| Streak | White | White (colorless) |
| Transparency | transparent | Transparent to opaque |
| Specific gravity | 2.7 | 3.0–3.25 |
| Crystal system | trigonal | Trigonal |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | Black, Green, Pink, Blue, Multicolored (watermelon) |
| Rarity | common | common |
| Typical specimen value | $2–$100+ | $2–$150+ |
Which is more valuable?
Tourmaline is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Tourmaline 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 Tourmaline
Tourmaline is not a single mineral but a group of complex borosilicates sharing a trigonal crystal structure and the general formula XY3Z6(BO3)3Si6O18(OH)4, with composition varying widely among species such as schorl, elbaite, and dravite. It has the widest color range of any mineral group, from jet-black schorl to multicolored elbaite crystals that can shift from pink to green along a single crystal, called watermelon tourmaline. It is also both piezoelectric and pyroelectric, generating an electric charge under pressure or heat.
Calcite vs Tourmaline FAQ
Is Calcite the same as Tourmaline?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Tourmaline is harder (Mohs 7–7.5) than Calcite (Mohs 3), so Tourmaline 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 Tourmaline?
Tourmaline is harder (Mohs 7–7.5) than Calcite (Mohs 3), so Tourmaline will scratch Calcite and not the other way round. A copper coin (Mohs 3.5) scratches it, but a fingernail does not. Streak color differs: Calcite leaves a white streak on unglazed porcelain, Tourmaline leaves white (colorless). Hold a thin edge to the light: Calcite is transparent, Tourmaline is Transparent to opaque.
Which is harder, Calcite or Tourmaline?
Tourmaline is harder: Mohs 7–7.5 against Mohs 3 for Calcite.
Which is more valuable, Calcite or Tourmaline?
Tourmaline is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Tourmaline can reach $150 or more.
