Greenschist

Physical Properties

Hardness: 3.5-4 (Mohs scale); Color: green to gray-green due to chlorite and epidote; Luster: dull to silky; Structure: foliated/schistose; Cleavage: perfect in one direction on mica flakes; Specific Gravity: 2.8–3.0

Formation & Geological History

Formed through regional metamorphism of mafic igneous rocks (like basalt) under low-temperature and high-pressure conditions, typically in subduction zones or mountain-building environments.

Uses & Applications

Used primarily as decorative stone, crushed stone for construction, and occasionally in landscaping.

Geological Facts

Greenschist gets its color from 'green' minerals like chlorite, actinolite, and epidote. It represents a specific metamorphic facies that helps geologists understand the pressure and temperature history of an area.

Field Identification & Locations

Identify by its distinctive greenish hue and scaly or flaky foliation. Common in orogenic belts and coastal regions where ancient oceanic crust has been uplifted.

Identified on: 5/3/2026

Mode: Standard