igneous
Rounded greenish stone, likely basalt or metamorphic greenstone
Probable fine-grained mafic rock; possible basalt (plagioclase–pyroxene) or greenschist-facies greenstone
AI-generated identification · may be incorrectDark olive-gray, dull to weakly earthy luster, fine-grained and rounded by abrasion; hardness roughly 5–6, no visible crystals or cleavage. The photograph alone cannot reliably distinguish basalt from altered volcanic rock or serpentinite.
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Physical properties
Dark olive-gray, dull to weakly earthy luster, fine-grained and rounded by abrasion; hardness roughly 5–6, no visible crystals or cleavage. The photograph alone cannot reliably distinguish basalt from altered volcanic rock or serpentinite.
Formation & geological history
Likely formed as volcanic basalt and later weathered or transported in sediment; if metamorphosed, it may represent altered oceanic crust. Exact age and formation environment require locality and laboratory testing.
Uses & applications
Common basalt is used as aggregate, road stone, landscaping material, and occasionally ornamental stone; this small specimen has little commercial value.
Geological facts
Its green color may reflect chlorite, epidote, actinolite, or serpentine rather than a single mineral. A streak, magnet test, density, and thin-section or X-ray analysis would improve identification.
Field identification & locations
Look for fine texture, heavy feel, dark color, and tiny pale feldspar grains; basalt commonly occurs in volcanic terrains and stream gravels worldwide. A strong magnetic response favors magnetite-bearing basalt.
