Comparison · Minerals vs Borate Minerals
Calcite vs Ulexite
Calcite and Ulexite are easy to confuse. 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 Ulexite
- 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 1.95 for Ulexite).
- Hold a thin edge to the light: Calcite is transparent, Ulexite is translucent.
- They overlap in clear, but Calcite also comes in yellow, orange, blue, green, and pink.
- Well-formed crystals give it away: Calcite is trigonal, Ulexite is triclinic.
Calcite vs Ulexite properties
| Property | Calcite | Ulexite |
|---|---|---|
| Type | Minerals | Borate Minerals |
| Mohs hardness | 3 | 2.5 |
| Luster | vitreous | vitreous |
| Streak | White | White |
| Transparency | transparent | translucent |
| Specific gravity | 2.7 | 1.95 |
| Crystal system | trigonal | triclinic |
| Common colors | Colorless, White, Yellow, Orange, Blue, Green, Pink | White, Colorless |
| Rarity | common | uncommon |
| Typical specimen value | $2–$100+ | $5–$120+ |
Which is more valuable?
Ulexite is usually the more valuable of the two: a typical collector specimen runs about $25 against $15 for Calcite, and premium Ulexite can reach $120 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 Ulexite
Ulexite is a hydrated sodium calcium borate best known for its fibrous variety, which transmits light along its fibers. Sliced and polished plates project an image from the back surface, earning it the nickname television stone.
Calcite vs Ulexite FAQ
Is Calcite the same as Ulexite?
No. Calcite is a mineral while Ulexite is a borate mineral. 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 Ulexite?
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 1.95 for Ulexite). Hold a thin edge to the light: Calcite is transparent, Ulexite is translucent.
Which is harder, Calcite or Ulexite?
Calcite is harder: Mohs 3 against Mohs 2.5 for Ulexite.
Which is more valuable, Calcite or Ulexite?
Ulexite is usually the more valuable of the two: a typical collector specimen runs about $25 against $15 for Calcite, and premium Ulexite can reach $120 or more.
