igneous
Likely weathered basaltic rock or slag-like volcanic specimen
Fine-grained mafic rock, probably basalt; exact identification requires testing
AI-generated identification · may be incorrectDark gray to black, dull to weakly vitreous luster, irregular rounded shape, and a rough lighter-gray weathered rim. Apparent hardness about 5–6 Mohs; crystals are too fine to resolve, and no clear cleavage is visible.
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Physical properties
Dark gray to black, dull to weakly vitreous luster, irregular rounded shape, and a rough lighter-gray weathered rim. Apparent hardness about 5–6 Mohs; crystals are too fine to resolve, and no clear cleavage is visible.
Formation & geological history
Basalt forms when iron- and magnesium-rich lava cools rapidly at or near the surface, commonly in volcanic fields; typical ages range from recent to billions of years. The rounded form likely reflects abrasion or weathering, though industrial slag cannot be excluded from the photograph.
Uses & applications
Basalt is used as aggregate, paving stone, railway ballast, and occasionally decorative stone. An ordinary specimen has little commercial or collector value.
Geological facts
The glossy dark patches may be fresh fractured basalt, but bubbles, glassy texture, or metal-like inclusions would suggest furnace slag instead. The reported Volgograd-region location is dominated by sedimentary deposits, so naturally transported basalt is possible but not locally typical.
Field identification & locations
Check for vesicles, magnetic response, and a streak: basalt is commonly weakly to strongly magnetic and leaves no colored streak; slag often has abundant bubbles, glass, or metallic droplets. Estimated value: $1–$10 if basalt; <$5 if common slag.
