Mineralpedia Details for Magnetite

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Magnetite

Magnetite is an old term that is possibly in reference to Magnesia in Greece which was a site for lodestone. Magnetite is a common mineral with thousands of localities worldwide. It is “a common accessory mineral in igneous and metamorphic rocks in which magmatic segregations or contact metamorphism may produce economically viable deposits [as well as] in sedimentary banded iron formations, [as] a biogenic product, [and in] important detrital deposits.” Magnetite, as one can determine from its name, is highly magnetic.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/magnetite.pdf

Formula: Fe²⁺Fe³⁺₂O₄
Crystal System: Isometric
Crystal Habit: Massive, Massive - Granular, Crystalline - Fine
Cleavage: None, None, None
Luster: Metallic
Color: grayish black, iron black
Streak: black
Class: Isometric - Hexoctahedral
Fracture: Sub Conchoidal
Hardness: 5.5-6
WebMineral: View Magnetite
Mindat: View Magnetite

Magnetite from Långban, Filipstad, Värmland, Sweden

Octahedral, brilliant Magnetite crystals to 5mm.

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Magnetite from Christie mine, Fresno Co., California, United States

Black, lustrous, octahedral crystals of Magneite to 6mm throughout Dolomite matrix.

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Magnetite from Binntal, Wallis, Switzerland

Excellent, sharp, octahedral crystals, the largest to 8mm across with several smaller and an unidentified red mineral, whih is probably Sphalerite. Old specimen from the University of Chicago with matching numbers on label and specimen. See Provenance tab.