metamorphic
Greenschist
Greenschist (containing Chlorite, Actinolite, and Epidote)
Hardness: 3.5-4.5 on Mohs scale; Color: Dull green to bright emerald green; Luster: Pearly to vitreous; Crystal Structure: Foliated or schistose texture; Cleavage: Good in one direction due to mica-like minerals; Specific Gravity: 2.8-3.0
- Hardness
- 3
- Color
- Dull green to bright emerald green
- Luster
- Pearly to vitreous
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Physical properties
Hardness: 3.5-4.5 on Mohs scale; Color: Dull green to bright emerald green; Luster: Pearly to vitreous; Crystal Structure: Foliated or schistose texture; Cleavage: Good in one direction due to mica-like minerals; Specific Gravity: 2.8-3.0
Formation & geological history
Formed through low-grade regional metamorphism of mafic igneous rocks (like basalt) at low temperatures (300-450°C) and moderate pressures. Commonly associated with mountain-building events and subduction zones.
Uses & applications
Used primarily as decorative stone, crushed stone for construction, and occasionally in landscaping. Historical use as building stone in specific regions where it is abundant.
Geological facts
The green color is primarily derived from minerals like chlorite, epidote, and actinolite. It defines the 'greenschist facies' in metamorphic geology, a specific range of temperature and pressure conditions.
Field identification & locations
Identify by its characteristic green hue and foliated (layered) texture that allows it to split into thin sheets. Found in metamorphic belts such as the Appalachian Mountains, the Alps, and the Scottish Highlands.
