Comparison · Minerals
Gypsum vs Talc
Gypsum and Talc are easy to confuse because both are minerals. Gypsum is harder (Mohs 2) than Talc (Mohs 1), so Gypsum will scratch Talc and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Gypsum and Talc
- Gypsum is harder (Mohs 2) than Talc (Mohs 1), so Gypsum will scratch Talc and not the other way round. A fingernail (Mohs 2.5) scratches it easily.
- Luster is different: Gypsum is vitreous, pearly, or silky (fibrous), earthy when massive while Talc is pearly to greasy/waxy.
- Hold a thin edge to the light: Gypsum is Transparent to translucent, Talc is Translucent to opaque.
- They overlap in gray and brown, but Gypsum also comes in clear, yellow, and pink and Talc also comes in white and green.
Gypsum vs Talc properties
| Property | Gypsum | Talc |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 2 | 1 |
| Luster | Vitreous, pearly, or silky (fibrous), earthy when massive | Pearly to greasy/waxy |
| Streak | White | White |
| Transparency | Transparent to translucent | Translucent to opaque |
| Specific gravity | 2.3–2.35 | 2.5–2.8 |
| Crystal system | Monoclinic | Monoclinic |
| Common colors | Colorless, White, Gray, Yellow, Brown, Pink | White, Pale green, Gray, Brown |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Gypsum and Talc trade in a similar range, around $20.
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.
About Talc
Talc is a hydrous magnesium silicate, Mg3Si4O10(OH)2, and the softest mineral known, defining hardness 1 on the Mohs scale, easily scratched by a fingernail. It forms through the hydrothermal alteration of magnesium-rich rocks like dolomite, serpentine, or ultramafic igneous rock, and has a distinctively greasy, soapy feel. Massive, compact talc is known as soapstone and has been carved for cookware, sculpture, and ornamental objects for thousands of years.
Gypsum vs Talc FAQ
Is Gypsum the same as Talc?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Gypsum is harder (Mohs 2) than Talc (Mohs 1), so Gypsum will scratch Talc and not the other way round. A fingernail (Mohs 2.5) scratches it easily.
How can you tell Gypsum from Talc?
Gypsum is harder (Mohs 2) than Talc (Mohs 1), so Gypsum will scratch Talc and not the other way round. A fingernail (Mohs 2.5) scratches it easily. Luster is different: Gypsum is vitreous, pearly, or silky (fibrous), earthy when massive while Talc is pearly to greasy/waxy. Hold a thin edge to the light: Gypsum is Transparent to translucent, Talc is Translucent to opaque.
Which is harder, Gypsum or Talc?
Gypsum is harder: Mohs 2 against Mohs 1 for Talc.
Which is more valuable, Gypsum or Talc?
Typical specimens of Gypsum and Talc trade in a similar range, around $20.
