metamorphic
Greenschist
Greenschist (Chlorite Schist facies)
Hardness: 3.5-4.5; Color: Dull green to dark green with yellowish-white phenocrysts; Luster: Waxy to pearly when wet; Structure: Foliated but often appears massive in water-worn cobbles; Composition: Rich in chlorite, epidote, and actinolite.
- Hardness
- 3
- Color
- Dull green to dark green with yellowish-white phenocrysts
- Luster
- Waxy to pearly when wet
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Physical properties
Hardness: 3.5-4.5; Color: Dull green to dark green with yellowish-white phenocrysts; Luster: Waxy to pearly when wet; Structure: Foliated but often appears massive in water-worn cobbles; Composition: Rich in chlorite, epidote, and actinolite.
Formation & geological history
Formed through low-grade regional metamorphism of mafic igneous rocks (like basalt or gabbro) under low temperatures and moderate pressures. Commonly associated with ancient seafloor subduction zones.
Uses & applications
Used primarily as decorative landscaping stone, crushed aggregate for construction, and occasionally for minor ornamental carvings due to its attractive green hue and softness.
Geological facts
The green color is primarily due to the presence of the mineral chlorite. This specimen shows a 'porphyroblastic' texture where larger crystals (likely feldspar or epidote) are embedded in a finer-grained green matrix.
Field identification & locations
Identify in the field by its characteristic green color and slightly soapy feel typical of chlorite-rich rocks. Often found in riverbeds near metamorphic belts or along coastlines with tectonic history. Collectors look for unique inclusions or smooth, water-worn shapes.
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