Greenschist is a metamorphic rock formed under low-to-medium pressure and temperature conditions, characterized by its distinct green color derived from minerals like chlorite and epidote. It often exhibits a foliated texture known as schistosity, where minerals align to create a layered appearance. It is a common indicator of regional metamorphism in orogenic belts.
Is this greenschist?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch greenschist with a known reference. Greenschist sits at Mohs 3-6, softer than the next harder reference, harder than the previous one.
- 2Read the textureLook at a fresh break with a hand lens. Texture: Schistose; splits into flakes or slabs under 5 to 10 mm thick.
- 3Pick out the mineralsComposition: Chlorite, epidote or actinolite, often with albite, quartz and muscovite. Identify the two or three most abundant grains.
- 4Read the lusterHold the specimen under a strong light. Luster: foliated.
- 5Match the color rangeCompare against the expected color range: green, dark green, light green.
Often confused with
Greenschist vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads foliated on Greenschist and subvitreous to pearly on Amphibolite.
How to tell apart: Greenschist is noticeably harder (Mohs 3-6 vs. 1-2); luster reads foliated on Greenschist and silky on Phyllite.
Often found alongside greenschist
Minerals reported to co-occur with greenschist. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Mohs hardness
- 3-6
- Density
- 2.7-3.0 g/cm³
- Luster
- Foliated
- Transparency
- Opaque
- Rarity
- Common
- Uses
- Construction, Decorative, Geological study
- Host rock
- metamorphic terranes
- Texture
- Schistose; splits into flakes or slabs under 5 to 10 mm thick
- Composition
- Chlorite, epidote or actinolite, often with albite, quartz and muscovite
Where rockhounds find greenschist
Classic worldwide localities
- Alps
- Appalachians
- Scotland
- New Zealand
- Scandinavia
Field-hunting tip
Where it forms: metamorphic terranes. If you start seeing chlorite, epidote, actinolite in float, you are in the right ground.
Common questions
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What rocks look like greenschist?+
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Find greenschist on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
