metamorphic
Greenschist
Greenschist (Chlorite-actinolite schist)
Hardness: 3.5-4.5; Color: Dark green to grey-green; Luster: Dull to silky; Crystal Structure: Foliated; Cleavage: Good in one direction; Specific Gravity: 2.8-3.0
- Hardness
- 3
- Color
- Dark green to grey-green
- Luster
- Dull to silky
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Physical properties
Hardness: 3.5-4.5; Color: Dark green to grey-green; Luster: Dull to silky; Crystal Structure: Foliated; Cleavage: Good in one direction; Specific Gravity: 2.8-3.0
Formation & geological history
Formed through low-temperature, high-pressure metamorphism (greenschist facies) of mafic igneous rocks like basalt or gabbro, typically during mountain-building events.
Uses & applications
Mainly used for decorative stone in gardens, historical building material, and occasionally as a source for crushed stone in construction.
Geological facts
The green color is primarily due to the presence of minerals like chlorite, epidote, and actinolite. It is a key indicator of the metamorphic grade of a region.
Field identification & locations
Identify by its characteristic green hue and fine-grained, foliated (layered) texture. Common in ancient mountain belts such as the Appalachians or the Scottish Highlands.
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