Rock Identifier
Hematite (Botryoidal/Kidney Ore) (Iron(III) oxide (Fe2O3)) — mineral
mineral

Hematite (Botryoidal/Kidney Ore)

Iron(III) oxide (Fe2O3)

Hardness: 5.5-6.5 on Mohs scale; Color: Steel-gray to black with a diagnostic reddish-brown streak; Luster: Metallic to sub-metallic; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 5.26.

Hardness
5
Color
Steel-gray to black with a diagnostic reddish-brown streak
Luster
Metallic to sub-metallic
Identified More mineral

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Physical properties

Hardness: 5.5-6.5 on Mohs scale; Color: Steel-gray to black with a diagnostic reddish-brown streak; Luster: Metallic to sub-metallic; Crystal structure: Trigonal; Cleavage: None; Specific gravity: 5.26.

Formation & geological history

Formed primarily through sedimentary processes in banded iron formations (BIFs) or via hydrothermal replacement and oxidation of other iron-bearing minerals. Common in ancient oxidized environments dating back up to 2.4 billion years.

Uses & applications

Primary ore of iron for steel production. Also used as a pigment (ochre), polishing rouge for jewelers, and as a popular semi-precious gemstone for beads and carvings.

Geological facts

Hematite gets its name from the Greek word 'haima' for blood, due to the red color of its powdered form. NASA's Opportunity rover discovered hematite 'blueberries' on Mars, suggesting Liquid water was once present there.

Field identification & locations

Identify in the field by its high density (feels heavy for its size) and the 'streak test' (rubbing it on unglazed porcelain produces a red streak). Common locations include the Lake Superior region (USA), Brazil, and Australia.