metamorphic

Greenstone

Metabasalt or Greenschist (often contains Chlorite, Actinolite, and Epidote)

AI-generated identification · may be incorrect

Hardness: 6-7 Mohs; Color: Pale to dark green; Luster: Dull to waxy; Structure: Finely crystalline to foliated; SG: 2.8-3.0

Hardness: 6-7 Mohs
Color: Pale to dark green
Luster: Dull to waxy

Identified June 29, 2026More metamorphic →

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Physical properties

Hardness: 6-7 Mohs; Color: Pale to dark green; Luster: Dull to waxy; Structure: Finely crystalline to foliated; SG: 2.8-3.0

Formation & geological history

Formed via low-grade regional metamorphism of mafic igneous rocks (like basalt) under high pressure and relatively low temperatures, often in subduction zones.

Uses & applications

Used historically for stone tools and weapons (like adzes), today used as crushed stone for construction, decorative landscaping, and occasionally lapidary work.

Geological facts

The green color is primarily due to the presence of chlorite, epidote, or actinolite. Some greenstones are over 2.5 billion years old and belong to ancient greenstone belts.

Field identification & locations

Identify by its distinct greenish hue and hardness (cannot be scratched by a steel nail). Commonly found in mountain belts and coastal regions with ancient tectonic activity.