mineral

Likely slag or metallic industrial byproduct

Unidentified iron-rich ferrous slag; possibly magnetite-bearing slag

AI-generated identification · may be incorrect

Dark gray to black, strongly metallic to submetallic luster with rough, vesicular texture and purple-blue oxidation colors. Hardness is roughly 5–6, with no obvious crystal cleavage; likely dense and potentially magnetic.

Identified August 9, 2026More mineral →

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Physical properties

Formation & geological history

The irregular, glassy-looking surface and oxidation staining suggest furnace slag rather than a natural rock, produced during iron or steel smelting. Its age is probably modern or historical, not geologic.

Uses & applications

Collected as an industrial-history specimen or curiosity; generally has little commercial or jewelry value and is unsuitable for structural construction without testing.

Geological facts

Slag can resemble meteorites, basalt, or metallic minerals, but bubbles, flow textures, glassy patches, and attached rust commonly indicate human processing. A magnet test may reveal abundant iron-bearing phases.

Field identification & locations

Inspect for vesicles, glassy flow bands, sharp irregular edges, and magnetic response; a streak test and density measurement can help distinguish it from hematite or magnetite. Common near old furnaces, foundries, rail works, mines, and smelters.