Comparison · Minerals
Calcite vs Howlite
Calcite and Howlite 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 Howlite
- Both sit near Mohs 3, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Hold a thin edge to the light: Calcite is transparent, Howlite is Opaque.
- Well-formed crystals give it away: Calcite is trigonal, Howlite is Monoclinic.
Calcite vs Howlite properties
| Property | Calcite | Howlite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 3 | 3–3.5 |
| Luster | vitreous | Subvitreous to dull |
| Streak | White | White |
| Transparency | transparent | Opaque |
| Specific gravity | 2.7 | 2.45–2.6 |
| Crystal system | trigonal | Monoclinic |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | White with gray veining |
| Rarity | common | common |
| Typical specimen value | $2–$100+ | $2–$150+ |
Which is more valuable?
Howlite is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Howlite 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 Howlite
Howlite is a calcium borosilicate hydroxide, Ca2B5SiO9(OH)5, typically found as white to gray nodular masses veined with dark, web-like markings that resemble turquoise. It crystallizes in the monoclinic system but rarely as distinct crystals, forming instead as compact, chalky nodules in borate-rich evaporite deposits. It was first described in 1868 by Canadian geologist Henry How, for whom it is named.
Calcite vs Howlite FAQ
Is Calcite the same as Howlite?
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 Howlite?
Both sit near Mohs 3, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hold a thin edge to the light: Calcite is transparent, Howlite is Opaque. Well-formed crystals give it away: Calcite is trigonal, Howlite is Monoclinic.
Which is harder, Calcite or Howlite?
They are about equally hard, both near Mohs 3.
Which is more valuable, Calcite or Howlite?
Howlite is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Howlite can reach $150 or more.
