metamorphic
Greenstone pebble
Greenstone, typically metamorphosed basalt or andesite; often contains chlorite, epidote, and actinolite
AI-generated identification · may be incorrectFine-grained, rounded gray-green stone with a dull to slightly waxy luster. Likely Mohs hardness 5–6; exact mineral composition and properties cannot be confirmed from an image.
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Physical properties
Fine-grained, rounded gray-green stone with a dull to slightly waxy luster. Likely Mohs hardness 5–6; exact mineral composition and properties cannot be confirmed from an image.
Formation & geological history
Forms when mafic volcanic rock is altered by low-grade metamorphism and fluids; the pebble’s age and source are not identifiable from the photo. Common in ancient volcanic belts and glacial or river gravels.
Uses & applications
Used as decorative stone, landscaping material, and occasionally for carving or jewelry; most small pebbles have modest value.
Geological facts
“Greenstone” describes a color and alteration assemblage, not one precise mineral species.
Field identification & locations
The smooth, water-worn shape and muted green-gray color are consistent with a river or beach pebble. Field identification is strengthened by checking for a fine grain and green chlorite or epidote; these are not discernible in the image.
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