mineral

Botryoidal Hematite (Kidney Ore)

Iron(III) oxide (Fe2O3)

Hardness: 5-6.5 (Mohs scale); Color: Metallic grey to rusty red-brown; Luster: Metallic to submetallic; Crystal Structure: Trigonal (often found in botryoidal or kidney-like masses); Cleavage: None; Specific Gravity: 5.26.

Hardness: 5-6
Color: Metallic grey to rusty red-brown
Luster: Metallic to submetallic

Identified June 8, 2026More mineral →

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Physical properties

Formation & geological history

Forms primarily in sedimentary environments through precipitation from iron-rich hydrothermal fluids or the weathering of iron-bearing minerals. Can be found in banded iron formations dating back billions of years.

Uses & applications

Primary ore of iron for steel production. Also used as a pigment (ochre), in jewelry as polished stones or beads, and as a popular mineral specimen for collectors.

Geological facts

The name is derived from the Greek word 'haima' meaning blood, due to the reddish streak it leaves when scratched. This specific bubbly appearance is called 'botryoidal,' which comes from the Greek word for a cluster of grapes.

Field identification & locations

Identified by its distinctive bubble-like texture and its reddish-brown streak. It is denser than most rocks of its size. Commonly found in mining districts of England (Cumbria), Morocco, Brazil, and the USA (Great Lakes region).

Other mineral specimens

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Schist

Metamorphic

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Biotite Schist

Biotite-rich Schist [K(Mg,Fe)3AlSi3O10(F,OH)2]

metamorphic