igneous
Tumbled greenstone / altered basalt pebble
Fine-grained mafic volcanic rock, likely basalt or greenstone; commonly composed of plagioclase, pyroxene, chlorite, epidote, and iron oxides
AI-generated identification · may be incorrectHardness typically 5.5–7 Mohs; muted olive-green to gray-green, fine-grained, opaque, and dull to slightly silky from polishing. Massive texture with no visible cleavage or distinct crystals; density commonly 2.8–3.1.
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Physical properties
Hardness typically 5.5–7 Mohs; muted olive-green to gray-green, fine-grained, opaque, and dull to slightly silky from polishing. Massive texture with no visible cleavage or distinct crystals; density commonly 2.8–3.1.
Formation & geological history
Likely formed as basaltic lava, then chemically altered by low-grade metamorphism or hydrothermal fluids; exact age cannot be determined from an image. The smooth oval shape indicates natural water abrasion and/or tumbling.
Uses & applications
Used as a decorative stone, worry stone, paperweight, and lapidary material; generally unsuitable for gemstone jewelry unless it has attractive patterning or unusual provenance.
Geological facts
Green coloration commonly results from chlorite, epidote, actinolite, or serpentine replacing original basalt minerals. A streak, hardness, and specific-gravity test would distinguish it from jade, serpentine, or manufactured glass.
Field identification & locations
Look for a uniformly fine texture, heavy feel, subdued green color, and lack of bubbles or glassy translucence; common in stream gravels and volcanic terrains. Exact identification requires testing or petrographic analysis.
