mineral

Likely iron-rich slag or weathered ironstone

Hematite–goethite-rich material (Fe₂O₃/FeO(OH)); possibly industrial iron slag

AI-generated identification · may be incorrect

Dark reddish-brown to black, glossy/earthy luster, irregular conchoidal-looking fracture, and no visible crystal faces. Hematite hardness is about 5–6.5 Mohs; goethite is 5–5.5, with typically high density and a red-brown streak.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

If natural, it may be ironstone formed by oxidation and concentration of iron minerals in weathering environments, commonly during the Cenozoic or older. Its bubbly, irregular appearance could instead indicate human-produced iron slag, which is not a natural rock but is still a geological-material specimen.

Uses & applications

Natural hematite and goethite are iron ores, pigments, and collectible minerals; slag is mainly an archaeological or industrial by-product with little commercial value.

Geological facts

A streak test is especially diagnostic: hematite gives a cherry-red to reddish-brown streak, while magnetite gives a black streak. Strong magnetism would suggest magnetite-bearing ironstone or slag.

Field identification & locations

Common natural sources include banded iron formations and lateritic soils; slag occurs near historic furnaces, mines, and metalworking sites. Test streak, magnetism, density, and look for glassy bubbles to distinguish ore from slag.