metamorphic

Greenschist (or Serpentinite with Manganese Dendrites)

Greenschist facies metamorphic rock

AI-generated identification · may be incorrect

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 July 24, 2026More metamorphic →

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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.