Comparison · Metamorphic Rocks
Mylonite vs Schist
Mylonite and Schist 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 Mylonite and Schist
- Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Luster is different: Mylonite is silky while Schist is vitreous to silky/glittery (mica-rich).
- Hold a thin edge to the light: Mylonite is opaque, Schist is Opaque.
- They overlap in gray, black, and green, but Mylonite also comes in white and brown and Schist also comes in yellow.
Mylonite vs Schist properties
| Property | Mylonite | Schist |
|---|---|---|
| Type | Metamorphic Rocks | Metamorphic Rocks |
| Mohs hardness | 5.5 | 2.5–7 |
| Luster | silky | Vitreous to silky/glittery (mica-rich) |
| Streak | Variable by mineral content | — |
| Transparency | opaque | Opaque |
| Specific gravity | 2.7 | 2.7–3.0 |
| Crystal system | varies | — |
| Common colors | Gray, Black, White, Green, Brown | Silver-gray, Golden (mica-rich), Green (chlorite/talc schist), Black |
| Rarity | uncommon | common |
| Typical specimen value | $1–$75+ | $1–$75+ |
Which is more valuable?
Typical specimens of Mylonite and Schist trade in a similar range, around $10.
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.
About Schist
Schist is a medium- to high-grade metamorphic rock defined by strong foliation from visible, aligned flakes of platy minerals like mica, giving it a pronounced sheen and a tendency to split along wavy surfaces. It forms through the continued metamorphism of shale, phyllite, or similar fine-grained rock under sustained heat and pressure, deep within mountain belts. Schist is typically named for its dominant mineral, such as mica schist, garnet schist, or chlorite schist.
Mylonite vs Schist FAQ
Is Mylonite the same as Schist?
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 Mylonite from Schist?
Both sit near Mohs 5.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Luster is different: Mylonite is silky while Schist is vitreous to silky/glittery (mica-rich). Hold a thin edge to the light: Mylonite is opaque, Schist is Opaque.
Which is harder, Mylonite or Schist?
Mylonite is harder: Mohs 5.5 against Mohs 2.5–7 for Schist.
Which is more valuable, Mylonite or Schist?
Typical specimens of Mylonite and Schist trade in a similar range, around $10.
