metamorphic
Greenstone, likely chlorite-rich schist
Chlorite schist; chiefly chlorite, actinolite/amphibole, feldspar, and quartz
AI-generated identification · may be incorrectHardness about 2–6, depending on composition; gray-green to moss-green, with a dull to silky luster and foliated, platy texture. Visible mica-like flakes and weak schistosity are characteristic; cleavage is mainly along the foliation.
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Physical properties
Hardness about 2–6, depending on composition; gray-green to moss-green, with a dull to silky luster and foliated, platy texture. Visible mica-like flakes and weak schistosity are characteristic; cleavage is mainly along the foliation.
Formation & geological history
Formed when mafic volcanic rock such as basalt underwent low- to medium-grade metamorphism, commonly during mountain building. Such rocks are typically Paleozoic to Precambrian, though age cannot be determined from the photo.
Uses & applications
Used locally as decorative stone, aggregate, or landscaping rock; attractive pieces may be sold as greenstone specimens, but it is generally not a gemstone.
Geological facts
The broad term “greenstone” also includes altered basalt, greenschist, and serpentinite, so exact identification requires hardness, streak, magnetism, and thin-section or chemical testing.
Field identification & locations
Common in metamorphic belts worldwide, including the Appalachians, Canadian Shield, New Zealand, and greenstone belts. Look for green color, foliation, flaky cleavage, and a lack of glassy volcanic texture.
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