Comparison · Metamorphic Rocks
Amphibolite vs Blueschist
Amphibolite and Blueschist are easy to confuse because both are metamorphic rocks. Both sit near Mohs 5.5, 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 Amphibolite and Blueschist
- Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Amphibolite leaves a variable; usually pale gray to white streak on unglazed porcelain, Blueschist leaves variable; usually pale gray.
- Luster is different: Amphibolite is dull while Blueschist is silky.
- They overlap in black, green, and gray, but Amphibolite also comes in white and red and Blueschist also comes in blue.
Amphibolite vs Blueschist properties
| Property | Amphibolite | Blueschist |
|---|---|---|
| Type | Metamorphic Rocks | Metamorphic Rocks |
| Mohs hardness | 5.5 | 5.5 |
| Luster | dull | silky |
| Streak | Variable; usually pale gray to white | Variable; usually pale gray |
| Transparency | opaque | opaque |
| Specific gravity | 3 | 3.1 |
| Crystal system | varies | varies |
| Common colors | Black, Dark green, Gray, White, Red | Blue, Blue gray, Gray, Green, Black |
| Rarity | common | uncommon |
| Typical specimen value | $1–$75+ | $5–$150+ |
Which is more valuable?
Blueschist is usually the more valuable of the two: a typical collector specimen runs about $30 against $10 for Amphibolite, and premium Blueschist can reach $150 or more.
About Amphibolite
Amphibolite is a dark, tough metamorphic rock made mostly of amphibole and plagioclase. It often appears black to dark green and may contain red garnets.
About Blueschist
Blueschist is a blue to blue-gray metamorphic rock linked to subduction zones. Its color often comes from blue amphibole minerals such as glaucophane.
Amphibolite vs Blueschist FAQ
Is Amphibolite the same as Blueschist?
No. Both are metamorphic rocks, but they are distinct rock types with different hardness, streak or luster. Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Amphibolite from Blueschist?
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Amphibolite leaves a variable; usually pale gray to white streak on unglazed porcelain, Blueschist leaves variable; usually pale gray. Luster is different: Amphibolite is dull while Blueschist is silky.
Which is harder, Amphibolite or Blueschist?
They are about equally hard, both near Mohs 5.5.
Which is more valuable, Amphibolite or Blueschist?
Blueschist is usually the more valuable of the two: a typical collector specimen runs about $30 against $10 for Amphibolite, and premium Blueschist can reach $150 or more.
