Rock Identifier
Iron Ore (Magnetite-Hematite) (Magnetite (Fe3O4) and Hematite (Fe2O3)) — mineral
mineral

Iron Ore (Magnetite-Hematite)

Magnetite (Fe3O4) and Hematite (Fe2O3)

Hardness: 5.5-6.5 on Mohs scale; Color: Black, steel-gray, or reddish-brown; Luster: Metallic to sub-metallic; Crystal structure: Isometric (Magnetite) or Rhombohedral (Hematite); Cleavage: None; Specific Gravity: 4.9-5.3.

Hardness
5
Color
Black, steel-gray, or reddish-brown
Luster
Metallic to sub-metallic
Identified More mineral

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Physical properties

Hardness: 5.5-6.5 on Mohs scale; Color: Black, steel-gray, or reddish-brown; Luster: Metallic to sub-metallic; Crystal structure: Isometric (Magnetite) or Rhombohedral (Hematite); Cleavage: None; Specific Gravity: 4.9-5.3.

Formation & geological history

Formed in igneous or metamorphic environments, often found in Banded Iron Formations (BIFs). Many large deposits date back to the Precambrian era (1.8 to 2.5 billion years ago) through chemical precipitation from seawater.

Uses & applications

Primary source of iron for steel production. Also used as a heavy media in mineral processing, as a pigment (ochre), and in radiation shielding. Minor use in jewelry (polished hematite).

Geological facts

Magnetite is the most magnetic naturally occurring mineral on Earth. When naturally magnetized, it is known as lodestone. These minerals have been crucial to human civilization since the Iron Age.

Field identification & locations

Identify by its heavy feel (high density), dark streak (Magnetite is black, Hematite is reddish-brown), and reaction to a magnet. Commonly found in large sedimentary iron deposits in regions like Australia, Brazil, and the Lake Superior region of North America.