Comparison · Minerals
Alabaster vs Gypsum
Alabaster and Gypsum are easy to confuse because both are minerals. Both sit near Mohs 1.5–2, 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 Alabaster and Gypsum
- Both sit near Mohs 1.5–2, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Hold a thin edge to the light: Alabaster is Translucent to opaque, Gypsum is Transparent to translucent.
- They overlap in pink, yellow, and gray, but Alabaster also comes in white and multicolored and Gypsum also comes in clear and brown.
Alabaster vs Gypsum properties
| Property | Alabaster | Gypsum |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 1.5–2 | 2 |
| Luster | Vitreous (crystalline); waxy to dull (massive) | Vitreous, pearly, or silky (fibrous), earthy when massive |
| Streak | White | White |
| Transparency | Translucent to opaque | Transparent to translucent |
| Specific gravity | 2.3 | 2.3–2.35 |
| Crystal system | Monoclinic | Monoclinic |
| Common colors | White, Cream, Pale pink, Yellowish, Gray, Banded | Colorless, White, Gray, Yellow, Brown, Pink |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Alabaster and Gypsum trade in a similar range, around $20.
About Alabaster
Alabaster is a fine-grained, massive variety of gypsum (calcium sulfate dihydrate, CaSO4·2H2O), prized since antiquity for carving because of its softness and ability to take a smooth polish. Unlike crystalline selenite, alabaster shows no visible crystal faces, appearing instead as a compact, sugary or waxy mass. Its low hardness and solubility in water set it apart from harder ornamental stones like marble, which it is often confused with by name alone.
About Gypsum
Gypsum is a soft, common evaporite mineral, calcium sulfate dihydrate with the formula CaSO4·2H2O, that defines hardness 2 on the Mohs scale and can be scratched with a fingernail. It precipitates from evaporating saline water and occurs in forms ranging from transparent selenite crystals to fibrous satin spar and massive alabaster. Gypsum is also the principal raw material used to manufacture plaster of Paris and drywall.
Alabaster vs Gypsum FAQ
Is Alabaster the same as Gypsum?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 1.5–2, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Alabaster from Gypsum?
Both sit near Mohs 1.5–2, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hold a thin edge to the light: Alabaster is Translucent to opaque, Gypsum is Transparent to translucent. They overlap in pink, yellow, and gray, but Alabaster also comes in white and multicolored and Gypsum also comes in clear and brown.
Which is harder, Alabaster or Gypsum?
They are about equally hard, both near Mohs 1.5–2.
Which is more valuable, Alabaster or Gypsum?
Typical specimens of Alabaster and Gypsum trade in a similar range, around $20.
