mineral
Botryoidal hematite (ironstone)
Hematite, Fe₂O₃; likely a botryoidal or massive iron-oxide specimen
AI-generated identification · may be incorrectDark reddish-brown to brown, earthy-to-submetallic luster, rounded/botryoidal and ridged surface; Mohs hardness 5–6.5, specific gravity about 5.0–5.3, commonly massive rather than visibly crystalline, with no prominent cleavage.
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Physical properties
Dark reddish-brown to brown, earthy-to-submetallic luster, rounded/botryoidal and ridged surface; Mohs hardness 5–6.5, specific gravity about 5.0–5.3, commonly massive rather than visibly crystalline, with no prominent cleavage.
Formation & geological history
Forms through oxidation and concentration of iron in hydrothermal veins, sedimentary iron formations, weathering zones, and caves; specimens may range from Precambrian iron-formation material to much younger secondary deposits.
Uses & applications
Used chiefly as iron ore and pigment; attractive polished pieces are collected, though this specimen appears more typical of a common hand specimen than jewelry grade.
Geological facts
Hematite produces a distinctive red-to-reddish-brown streak, even when the surface is nearly black; this is the best confirmation test. It is denser than most brown host rocks and may weakly attract a magnet if mixed with magnetite.
Field identification & locations
Common localities include Brazil, Australia, South Africa, the Lake Superior region, and Morocco. Test an inconspicuous area with an unglazed porcelain tile: a red streak strongly supports hematite; avoid confusing it with limonite or magnetite.
