metamorphic
Greenschist
Chlorite Schist (Greenschist Facies)
Hardness: 2-3.5 (soft). Color: Dull green, gray-green, to olive. Luster: Pearly to silky due to mica/chlorite. Structure: Foliated (schistose) with a platy or flaky appearance. Cleavage: Perfect in one direction on individual mica grains.
- Hardness
- 2-3
- Color
- Dull green, gray-green, to olive
- Luster
- Pearly to silky due to mica/chlorite
Identified More metamorphic →
Explore Greenschist in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 2-3.5 (soft). Color: Dull green, gray-green, to olive. Luster: Pearly to silky due to mica/chlorite. Structure: Foliated (schistose) with a platy or flaky appearance. Cleavage: Perfect in one direction on individual mica grains.
Formation & geological history
Formed by the low-grade metamorphism of mafic igneous rocks (like basalt) or volcanic tuffs under high pressure and low temperatures (roughly 300C to 450C). Usually found in mountain belts where tectonic plates collide.
Uses & applications
Mainly of interest to geologists and collectors. Sometimes used as decorative garden stone or as low-durability building stone (flagstone) in specific local contexts.
Geological facts
The 'green' in greenschist comes from minerals like chlorite, epidote, and actinolite. The presence of these minerals indicates the specific thermal history the rock underwent, known by geologists as the 'greenschist facies'.
Field identification & locations
Identify by its distinct greenish hue and tendency to split into thin, somewhat rough sheets. Often found near subduction zones or ancient mountain ranges. It will often feel slightly 'greasy' or soapy due to the high chlorite content.
More like this
