RocksdayGreenschist vs Serpentinite
How to tell them apart
A green, flaky metamorphic rock rich in chlorite, epidote and actinolite.
Photo: No machine-readable author provided. Siim assumed (based on copyright claims)., CC BY-SA 3.0
Rock of serpentine minerals, formed when mantle rock reacts with seawater. Slick, green and mottled.
Photo: Gabriel HM, CC BY-SA 4.0
Key differences
- Serpentinite is waxy and massive.
Side by side
| Property | Greenschist | Serpentinite |
|---|---|---|
| Type | Metamorphic rock | Metamorphic rock |
| Mohs hardness | 3–5 | 3–5 |
| Luster | Silky to dull | Waxy to greasy |
| Colors | Green | Green, Black |
| Crystal system / structure | Foliated, chlorite-rich | Massive, often sheared |
| Specific gravity | 2.7–3 | 2.5–2.8 |
| Found in | Appalachian Mountains; Alps | California Coast Ranges; Newfoundland |
Properties that are the same for both are grayed out.
How to identify greenschist
- Green and foliated.
- Soft, slightly greasy flakes.
- Often with yellow-green epidote.
Structure: Foliated, chlorite-rich
Full Greenschist guide →How to identify serpentinite
- Green to black with a waxy, slippery look.
- Polished, scaly surfaces where it was sheared.
- Softer than it looks.
Structure: Massive, often sheared
Full Serpentinite guide →More comparisons
Could you tell them apart from a blurry close-up?
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