
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
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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.
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