metamorphic or igneous alteration
Greenish rock with white veins, possibly epidote or chlorite bearing rock with quartz/calcite veins
Altered mafic rock or Epidosite
Hardness varies, typically 5-7. Greenish-black to olive green color with white intersecting veins. Massive or granular structure.
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Physical properties
Hardness varies, typically 5-7. Greenish-black to olive green color with white intersecting veins. Massive or granular structure.
Formation & geological history
Formed through hydrothermal alteration or low-grade metamorphism of mafic igneous rocks (like basalt). Veins indicate fluid flow fracturing the rock and depositing quartz or calcite.
Uses & applications
Mostly collected by rockhounds. Sometimes larger, attractive pieces are polished for decorative purposes.
Geological facts
The green color in such rocks is often due to the presence of epidote, chlorite, or actinolite, which are typical minerals in greenschist facies metamorphism.
Field identification & locations
Identify by its greenish color and contrasting white veins. Can be found in areas with ancient volcanic activity or regional metamorphism. Veins can be tested with acid; calcite will fizz, quartz will not.
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