Comparison · Minerals
Calcite vs Heulandite
Calcite and Heulandite are easy to confuse because both are minerals. Both sit near Mohs 3, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Calcite and Heulandite
- Both sit near Mohs 3, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Calcite feels noticeably heavier for its size (specific gravity 2.7 versus 2.1–2.2 for Heulandite).
- Hold a thin edge to the light: Calcite is transparent, Heulandite is Transparent to translucent.
- They overlap in clear, yellow, and pink, but Calcite also comes in orange, blue, and green and Heulandite also comes in red and brown.
- Well-formed crystals give it away: Calcite is trigonal, Heulandite is Monoclinic.
Calcite vs Heulandite properties
| Property | Calcite | Heulandite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 3 | 3.5–4 |
| Luster | vitreous | Vitreous, pearly on cleavage |
| Streak | White | White |
| Transparency | transparent | Transparent to translucent |
| Specific gravity | 2.7 | 2.1–2.2 |
| Crystal system | trigonal | Monoclinic |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | White, Colorless, Pink, Red, Brown, Yellow |
| Rarity | common | common |
| Typical specimen value | $2–$100+ | $2–$150+ |
Which is more valuable?
Heulandite is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Heulandite 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 Heulandite
Heulandite is a calcium- and sodium-bearing zeolite mineral, part of a group known for its coffin-shaped monoclinic crystals with a distinctive pearly luster on one prominent cleavage face. It typically forms as a secondary mineral filling vesicles and fractures in basaltic and volcanic rocks, alongside other zeolites deposited by cooling hydrothermal fluids. Heulandite is named after English mineral collector Henry Heuland, whose collection contributed significantly to early zeolite mineralogy.
Calcite vs Heulandite FAQ
Is Calcite the same as Heulandite?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 3, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Calcite from Heulandite?
Both sit near Mohs 3, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Calcite feels noticeably heavier for its size (specific gravity 2.7 versus 2.1–2.2 for Heulandite). Hold a thin edge to the light: Calcite is transparent, Heulandite is Transparent to translucent.
Which is harder, Calcite or Heulandite?
Heulandite is harder: Mohs 3.5–4 against Mohs 3 for Calcite.
Which is more valuable, Calcite or Heulandite?
Heulandite is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Heulandite can reach $150 or more.
