metamorphic
Greenschist
Chlorite Schist
Hardness: 2-3 (Mohs scale), Color: dull green to bright green, Luster: silky or pearly on foliation planes, Crystal Structure: Monoclinic, Cleavage: perfect basal cleavage, Specific Gravity: 2.6-3.3
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Physical properties
Hardness: 2-3 (Mohs scale), Color: dull green to bright green, Luster: silky or pearly on foliation planes, Crystal Structure: Monoclinic, Cleavage: perfect basal cleavage, Specific Gravity: 2.6-3.3
Formation & geological history
Formed through low-grade regional metamorphism of mafic igneous rocks (like basalt) or sedimentary rocks under high pressure and low temperature (300-450 degrees Celsius). Common in mountain-building zones.
Uses & applications
Primarily used as a decorative building stone, in landscaping, and sometimes as a source for extracting magnesium or iron if rich in specific minerals.
Geological facts
The green color is primarily due to the presence of chlorite, epidote, or actinolite. It defines a specific 'Greenschist Facies' in metamorphic geology, indicating stable pressure and temperature conditions.
Field identification & locations
Identifiable by its distinct green hue and strongly foliated (platy) texture that allows it to split into thin sheets. Common in the Appalachian Mountains, the Alps, and the Scottish Highlands.
