metamorphic
Greenschist (or Serpentinite with Manganese Dendrites)
Greenschist facies metamorphic rock
Hardness 3.5-5.5 on Mohs scale; dull to earthy luster; fine-grained grayish-green matrix with dark black branching dendritic formations (manganese oxides) on the surface; irregular, blocky fracture.
Identified More metamorphic →
Explore Greenschist (or Serpentinite with Manganese Dendrites) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness 3.5-5.5 on Mohs scale; dull to earthy luster; fine-grained grayish-green matrix with dark black branching dendritic formations (manganese oxides) on the surface; irregular, blocky fracture.
Formation & geological history
Formed through low-grade regional metamorphism of basalt, gabbro, or rich mafic igneous rocks under low temperatures and moderate pressures, often associated with subduction zones or mountain-building events.
Uses & applications
Used primarily as decorative landscaping stone, crushed aggregate, carving material (if soft enough like soapstone/talc-rich varieties), and geological specimens for collectors.
Geological facts
The black tree-like patterns visible on the surface are manganese oxide dendrites. These form when mineral-rich water seeps into micro-cracks in the rock, precipitating manganese in crystal patterns that resemble fossilized plants (pseudo-fossils).
Field identification & locations
Identified by its distinctive pale grayish-green hue, fine-grained metamorphic texture, and contrast with dark black surface dendrites. Commonly found in metamorphic terranes, riverbeds, and ancient subduction zones worldwide.
More like this
