igneous
Weathered mafic rock (likely basalt or greenstone)
Altered basalt, possibly metamorphosed to greenschist; exact identification requires testing
AI-generated identification · may be incorrectFine-grained, dull and earthy brown-green surface with scattered dark and pale mineral grains; likely plagioclase and pyroxene altered to chlorite/epidote. Hardness and crystal structure cannot be determined reliably from the image.
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Physical properties
Fine-grained, dull and earthy brown-green surface with scattered dark and pale mineral grains; likely plagioclase and pyroxene altered to chlorite/epidote. Hardness and crystal structure cannot be determined reliably from the image.
Formation & geological history
Likely formed as basaltic lava, then weathered or mildly metamorphosed; basalt commonly forms in volcanic settings from the Precambrian to the present.
Uses & applications
Basalt is used as aggregate, paving stone, and construction material; altered specimens are mainly collected or used decoratively.
Geological facts
Greenish hues can result from alteration minerals such as chlorite or epidote, while brown coloration commonly reflects iron-oxide weathering.
Field identification & locations
Look for a dense, fine-grained texture and small crystals; a fresh broken surface, hardness test, and mineral examination would help distinguish basalt from greenstone or another altered rock. Basalt is widespread in volcanic regions worldwide.
