Comparison · Minerals vs Quartz Family
Calcite vs Quartz
Calcite and Quartz are easy to confuse. Quartz is harder (Mohs 7) than Calcite (Mohs 3), so Quartz 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 Quartz
- Quartz is harder (Mohs 7) than Calcite (Mohs 3), so Quartz 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, Quartz is Transparent to translucent.
- They overlap in clear, yellow, and pink, but Calcite also comes in orange, blue, and green and Quartz also comes in purple, black, gray, and brown.
- Well-formed crystals give it away: Calcite is trigonal, Quartz is Trigonal.
Calcite vs Quartz properties
| Property | Calcite | Quartz |
|---|---|---|
| Type | Minerals | Quartz Family |
| Mohs hardness | 3 | 7 |
| Luster | vitreous | Vitreous, greasy on fracture surfaces |
| Streak | White | White |
| Transparency | transparent | Transparent to translucent |
| Specific gravity | 2.7 | 2.65 |
| Crystal system | trigonal | Trigonal |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | Colorless, White, Purple (amethyst), Yellow (citrine), Pink (rose), Brown/black (smoky) |
| Rarity | common | common |
| Typical specimen value | $2–$100+ | $5–$250+ |
Which is more valuable?
Quartz is usually the more valuable of the two: a typical collector specimen runs about $35 against $15 for Calcite, and premium Quartz 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 Quartz
Quartz is silicon dioxide, SiO2, one of the most abundant minerals in Earth's continental crust, crystallizing in the trigonal division of the hexagonal crystal system with a hardness of 7 that makes it a standard reference point on the Mohs scale. Its six-sided prismatic crystals, often terminated by pyramidal points, are among the most recognizable crystal shapes in mineralogy. Quartz occurs in nearly every rock type and geologic setting, from granite pegmatites to sedimentary sandstones to hydrothermal veins.
Calcite vs Quartz FAQ
Is Calcite the same as Quartz?
No. Calcite is a mineral while Quartz is a quartz family. Quartz is harder (Mohs 7) than Calcite (Mohs 3), so Quartz 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 Quartz?
Quartz is harder (Mohs 7) than Calcite (Mohs 3), so Quartz 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, Quartz is Transparent to translucent. They overlap in clear, yellow, and pink, but Calcite also comes in orange, blue, and green and Quartz also comes in purple, black, gray, and brown.
Which is harder, Calcite or Quartz?
Quartz is harder: Mohs 7 against Mohs 3 for Calcite.
Which is more valuable, Calcite or Quartz?
Quartz is usually the more valuable of the two: a typical collector specimen runs about $35 against $15 for Calcite, and premium Quartz can reach $250 or more.
