igneous
Likely polished basalt or iron-rich metamorphic rock
Basaltic rock, chiefly plagioclase and pyroxene; exact identification requires testing
AI-generated identification · may be incorrectDark gray-black, smooth glossy surface with a rough granular broken face. Likely hardness about 5–6 Mohs, nonmetallic to weakly submetallic luster, fine-grained crystalline texture, no obvious cleavage, and specific gravity roughly 2.8–3.3.
Identified More igneous →
Explore Likely polished basalt or iron-rich metamorphic rock in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark gray-black, smooth glossy surface with a rough granular broken face. Likely hardness about 5–6 Mohs, nonmetallic to weakly submetallic luster, fine-grained crystalline texture, no obvious cleavage, and specific gravity roughly 2.8–3.3.
Formation & geological history
Probably an eroded or broken volcanic rock formed from rapidly cooled mafic lava, generally Paleozoic or younger in age. Around 36.1°N, 83.4°W in eastern Tennessee, metamorphic rocks and iron-rich minerals are more regionally plausible than fresh basalt, so a dark metamorphic rock or slag-like ironstone is an alternative.
Uses & applications
Common basalt has uses as aggregate, road stone, and landscaping material; attractive polished pieces may be used decoratively. This specimen appears to have little commercial value, typically about $1–$10 unless proven to be an unusual mineral or meteorite.
Geological facts
The glossy side may be naturally weathered or polished, while the granular face appears freshly broken. It does not visibly show the glassy fusion crust, regmaglypts, or metallic iron commonly expected in a meteorite.
Field identification & locations
Test with a steel knife or glass, inspect for vesicles, and use a magnet. Strong magnetism and unusually high density could indicate magnetite-rich rock; a vinegar test is generally unhelpful. A streak test, specific-gravity measurement, and thin-section or XRF analysis would be needed for confident identification.
