metamorphic
Greenschist with Quartz Veining
Greenschist (commonly containing Chlorite, Actinolite, and Epidote)
Hardness: 3.5-5 (Mohs scale); Color: Dark green to grayish-green with white veins; Luster: Dull to pearly/silky; Structure: Foliated/schistose texture; Cleavage: Excellent in one direction (slaty/schistose cleavage); Specific Gravity: 2.8-3.0.
- Hardness
- 3
- Color
- Dark green to grayish-green with white veins
- Luster
- Dull to pearly/silky
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3.5-5 (Mohs scale); Color: Dark green to grayish-green with white veins; Luster: Dull to pearly/silky; Structure: Foliated/schistose texture; Cleavage: Excellent in one direction (slaty/schistose cleavage); Specific Gravity: 2.8-3.0.
Formation & geological history
Formed through low-grade regional metamorphism of mafic igneous rocks (like basalt) at temperatures of 300 to 450 degrees Celsius and moderate pressure. The white veins are typically quartz or calcite that filled fractures via hydrothermal fluids post-metamorphism.
Uses & applications
Used primarily as decorative landscaping stone, crushed stone for road construction, and occasionally as dimension stone for architectural facings. Sometimes used in rock gardens due to its aesthetic veining.
Geological facts
The 'green' in greenschist comes from minerals like chlorite and epidote. This rock is a key indicator of 'greenschist facies,' a specific range of metamorphic conditions that geologists use to map the history of mountain-building events.
Field identification & locations
Identify in the field by its characteristic green hue and fissile (splittable) nature. It often feels slightly soapy if chlorite is abundant. Common in mountain belts like the Appalachians, the Alps, and coastal ranges of California and the Pacific Northwest.
More like this
