sedimentary
Hematite-rich Ironstone
Ferruginous Rock (Fe2O3)
Hardness: 5.5-6.5; Color: Reddish-brown to steel grey; Luster: Metallic to earthy; Structure: Often massive or oolitic; Specific Gravity: 5.0-5.3
- Hardness
- 5
- Color
- Reddish-brown to steel grey
- Luster
- Metallic to earthy
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Physical properties
Hardness: 5.5-6.5; Color: Reddish-brown to steel grey; Luster: Metallic to earthy; Structure: Often massive or oolitic; Specific Gravity: 5.0-5.3
Formation & geological history
Formed primarily through the precipitation of iron from sea or lake water, often in Precambrian Banded Iron Formations (BIFs) dating back 2.4 billion years.
Uses & applications
Main ore of iron for steel production; used as pigments (ochre), in heavy media separation, and occasionally for jewelry/beads.
Geological facts
Hematite is responsible for the red color of many soils worldwide and even the surface of Mars. It is non-magnetic in its pure form but can contain magnetite inclusions.
Field identification & locations
Identify by its characteristic cherry-red streak when rubbed on unglazed porcelain. Commonly found in large sedimentary basins in Australia, Brazil, and the Lake Superior region.
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