Comparison · Minerals
Atacamite vs Celestine
Atacamite and Celestine are easy to confuse because both are minerals. Both sit near Mohs 3–3.5, 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 Atacamite and Celestine
- Both sit near Mohs 3–3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Atacamite leaves a apple green streak on unglazed porcelain, Celestine leaves white.
- They overlap in green, but Celestine also comes in clear, blue, gray, and orange.
Atacamite vs Celestine properties
| Property | Atacamite | Celestine |
|---|---|---|
| Type | Minerals | Minerals |
| Mohs hardness | 3–3.5 | 3–3.5 |
| Luster | Vitreous to adamantine | Vitreous, pearly on cleavage |
| Streak | Apple green | White |
| Transparency | Transparent to translucent | Transparent to translucent |
| Specific gravity | 3.75–3.77 | 3.95–3.97 |
| Crystal system | Orthorhombic | Orthorhombic |
| Common colors | Bright green, Dark green | Colorless, Pale blue, White, Gray, Light green, Orange (rare) |
| Rarity | common | common |
| Typical specimen value | $2–$150+ | $2–$150+ |
Which is more valuable?
Typical specimens of Atacamite and Celestine trade in a similar range, around $20.
About Atacamite
Atacamite is a copper chloride hydroxide mineral, Cu2Cl(OH)3, that forms a striking emerald to blackish-green secondary mineral in the oxidized zones of copper deposits. It takes its name from the Atacama Desert of Chile, where it was first described and where arid conditions allow chloride-bearing copper minerals to persist rather than being washed away. Atacamite is notable among copper minerals for containing structural chlorine, which ties its formation to saline or coastal environments.
About Celestine
Celestine, also spelled celestite, is strontium sulfate, SrSO4, and the primary ore of strontium, crystallizing in the orthorhombic system. It is best known for growing in delicate pale blue, tabular crystals, a color that gave the mineral its name from the Latin caelestis, meaning heavenly. Celestine often forms alongside gypsum and calcite in sedimentary evaporite settings, distinguishing it from most other sulfate minerals of hydrothermal origin.
Atacamite vs Celestine FAQ
Is Atacamite the same as Celestine?
No. Both are minerals, but they are distinct species with different hardness, streak or luster. Both sit near Mohs 3–3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Atacamite from Celestine?
Both sit near Mohs 3–3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Atacamite leaves a apple green streak on unglazed porcelain, Celestine leaves white. They overlap in green, but Celestine also comes in clear, blue, gray, and orange.
Which is harder, Atacamite or Celestine?
They are about equally hard, both near Mohs 3–3.5.
Which is more valuable, Atacamite or Celestine?
Typical specimens of Atacamite and Celestine trade in a similar range, around $20.
