igneous
Weathered iron-rich rock fragment
Indeterminate; likely basaltic or mafic rock with iron-oxide staining
AI-generated identification · may be incorrectDark brown to gray, fine-grained, dull to weakly earthy luster, irregular massive structure, and no visible cleavage; estimated Mohs hardness 5–6 and specific gravity roughly 2.8–3.3. The rusty coloration likely reflects hematite/goethite alteration.
Identified More igneous →
Explore Weathered iron-rich rock fragment in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark brown to gray, fine-grained, dull to weakly earthy luster, irregular massive structure, and no visible cleavage; estimated Mohs hardness 5–6 and specific gravity roughly 2.8–3.3. The rusty coloration likely reflects hematite/goethite alteration.
Formation & geological history
Probably a naturally weathered terrestrial rock, potentially basalt, gabbro, or another mafic fragment altered by oxidation; age and exact formation environment cannot be determined from the photograph. Its rounded, abraded form suggests transport by water or sediment.
Uses & applications
Unlikely to have commercial value; suitable mainly as a teaching or curiosity specimen. Mafic rocks are used as aggregate, road stone, riprap, and occasionally ornamental stone.
Geological facts
The image does not show diagnostic crystals, fossils, meteorite fusion crust, or a reliable cut surface, so precise identification requires testing. A magnet response, streak, fresh fracture, and density measurement would be useful.
Field identification & locations
Commonly found in stream gravels, weathered outcrops, glacial deposits, and construction fill. Check for a gray-black fresh interior, weak magnetism, and a reddish-brown streak; a strong metallic streak or glassy fusion crust would suggest a different material.
