mineral
Iron-rich breccia or hematite-bearing ironstone
Hematite–goethite ironstone, possibly brecciated jasper; chiefly Fe₂O₃ and FeO(OH)
AI-generated identification · may be incorrectDark reddish-brown to black, earthy to submetallic luster, granular and irregularly brecciated texture; hematite hardness ~5–6.5 Mohs, goethite ~5–5.5, with no obvious cleavage and relatively high specific gravity (~4–5).
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Physical properties
Dark reddish-brown to black, earthy to submetallic luster, granular and irregularly brecciated texture; hematite hardness ~5–6.5 Mohs, goethite ~5–5.5, with no obvious cleavage and relatively high specific gravity (~4–5).
Formation & geological history
Forms through oxidation and weathering of iron-rich rocks or hydrothermal precipitation, commonly cementing fractured material; exact geological age cannot be determined from the photograph.
Uses & applications
Primarily an iron ore and mineral-collecting specimen; attractive polished pieces may be used ornamentally, but this rough piece has little commercial value.
Geological facts
The red-brown coloration reflects oxidized iron minerals, while black areas may be hematite or manganese oxides; a reddish-brown streak on unglazed ceramic would support hematite/goethite identification.
Field identification & locations
Common in banded iron formations, weathering zones, laterites, and hydrothermal veins worldwide, especially Australia, Brazil, India, and the Lake Superior region. Test streak, heft, and magnetism; visual identification alone is uncertain.
