metamorphic
Tumbled greenstone/chlorite-rich pebble
Likely chlorite-rich greenschist or altered basalt; exact identification requires testing
AI-generated identification · may be incorrectDark olive-green, opaque, smooth and glossy from tumbling/polishing, with fine-grained texture and no visible crystals. Likely Mohs hardness 5–6; cleavage is not apparent and specific gravity is approximately 2.8–3.1.
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Physical properties
Dark olive-green, opaque, smooth and glossy from tumbling/polishing, with fine-grained texture and no visible crystals. Likely Mohs hardness 5–6; cleavage is not apparent and specific gravity is approximately 2.8–3.1.
Formation & geological history
Probably formed by low-grade metamorphism or hydrothermal alteration of basalt, converting mafic minerals to chlorite, epidote, and amphibole; commonly Paleozoic to Precambrian in source terrains, though age cannot be determined visually.
Uses & applications
Used as a decorative tumbled stone, cabochon, paperweight, or landscaping material; generally not a high-value gemstone.
Geological facts
Its green color commonly reflects chlorite and epidote rather than copper minerals. A glassy surface here is produced by polishing, not natural luster.
Field identification & locations
Common in stream gravels and metamorphic belts; identify with a streak, hardness, and magnetism test, and inspect under magnification for epidote or amphibole grains. It could also be serpentine or nephrite, which require testing to distinguish.
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