Comparison · Minerals
Borax vs Calcite
Borax and Calcite are easy to confuse because both are minerals. Both sit near Mohs 2–2.5, 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 Borax and Calcite
- Both sit near Mohs 2–2.5, 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 1.7 for Borax).
- Hold a thin edge to the light: Borax is Transparent to translucent, Calcite is transparent.
- They overlap in clear, but Borax also comes in gray and Calcite also comes in yellow, orange, blue, green, and pink.
- Well-formed crystals give it away: Borax is Monoclinic, Calcite is trigonal.
Borax vs Calcite properties
| Property | Borax | Calcite |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 2–2.5 | 3 |
| Luster | Vitreous to resinous, earthy when dehydrated | vitreous |
| Streak | White | White |
| Transparency | Transparent to translucent | transparent |
| Specific gravity | 1.7 | 2.7 |
| Crystal system | Monoclinic | trigonal |
| Common colors | White, Colorless, Gray | Colorless, White, Yellow, Orange, Blue, Green, Pink |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$100+ |
Which is more valuable?
Borax is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Borax can reach $150 or more.
About Borax
Borax is a hydrated sodium borate mineral, Na2B4O7·10H2O, that crystallizes from the evaporation of alkaline lakes in arid basins. It has been mined and used by humans for thousands of years as a cleaning agent, flux, and preservative, making it one of the more historically significant evaporite minerals. Borax dissolves readily in water and gives off a sweetish alkaline taste, reflecting its high solubility compared to most rock-forming minerals.
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.
Borax vs Calcite FAQ
Is Borax the same as Calcite?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 2–2.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Borax from Calcite?
Both sit near Mohs 2–2.5, 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 1.7 for Borax). Hold a thin edge to the light: Borax is Transparent to translucent, Calcite is transparent.
Which is harder, Borax or Calcite?
Calcite is harder: Mohs 3 against Mohs 2–2.5 for Borax.
Which is more valuable, Borax or Calcite?
Borax is usually the more valuable of the two: a typical collector specimen runs about $20 against $15 for Calcite, and premium Borax can reach $150 or more.
