Comparison · Metamorphic Rocks
Greenschist vs Mylonite
Greenschist and Mylonite are easy to confuse because both are metamorphic rocks. Mylonite is harder (Mohs 5.5) than Greenschist (Mohs 4.5), so Mylonite will scratch Greenschist and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Greenschist and Mylonite
- Mylonite is harder (Mohs 5.5) than Greenschist (Mohs 4.5), so Mylonite will scratch Greenschist and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
- Streak color differs: Greenschist leaves a variable; usually pale greenish gray streak on unglazed porcelain, Mylonite leaves variable by mineral content.
- They overlap in green, gray, black, and white, but Mylonite also comes in brown.
Greenschist vs Mylonite properties
| Property | Greenschist | Mylonite |
|---|---|---|
| Type | Metamorphic Rocks | Metamorphic Rocks |
| Mohs hardness | 4.5 | 5.5 |
| Luster | silky | silky |
| Streak | Variable; usually pale greenish gray | Variable by mineral content |
| Transparency | opaque | opaque |
| Specific gravity | 2.9 | 2.7 |
| Crystal system | varies | varies |
| Common colors | Green, Gray green, Dark green, Black, White | Gray, Black, White, Green, Brown |
| Rarity | common | uncommon |
| Typical specimen value | $1–$75+ | $1–$75+ |
Which is more valuable?
Typical specimens of Greenschist and Mylonite trade in a similar range, around $10.
About Greenschist
Greenschist is a greenish metamorphic rock named for its common green minerals and schistose texture. It often looks green, gray-green, or dark green and may have a silky sheen.
About Mylonite
Mylonite is a fine-grained, streaky metamorphic rock formed by intense ductile shearing in fault zones. It can show stretched mineral bands and a strong fabric.
Greenschist vs Mylonite FAQ
Is Greenschist the same as Mylonite?
No. Both are metamorphic rocks, but they are distinct rock types with different hardness, streak or luster. Mylonite is harder (Mohs 5.5) than Greenschist (Mohs 4.5), so Mylonite will scratch Greenschist and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
How can you tell Greenschist from Mylonite?
Mylonite is harder (Mohs 5.5) than Greenschist (Mohs 4.5), so Mylonite will scratch Greenschist and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Streak color differs: Greenschist leaves a variable; usually pale greenish gray streak on unglazed porcelain, Mylonite leaves variable by mineral content. They overlap in green, gray, black, and white, but Mylonite also comes in brown.
Which is harder, Greenschist or Mylonite?
Mylonite is harder: Mohs 5.5 against Mohs 4.5 for Greenschist.
Which is more valuable, Greenschist or Mylonite?
Typical specimens of Greenschist and Mylonite trade in a similar range, around $10.
