Magnesioferrite is a magnesium iron oxide mineral, a member of the magnetite series of spinels. It is the mineral magnesium iron oxide, a member of the magnetite (q.v.) series of spinels. It is a magnetic usually black mineral MgFe2O4 consisting of an oxide of magnesium and iron and constituting a member of the magnetite series
It is named after its chemical composition of magnesium and ferric iron.
General Information
- Category: Oxide minerals (Spinel group )
- Formula: Mg(Fe3+)2O4
- Crystal system: Cubic
- Crystal class: Hexoctahedral (m3m)
- Color: Black to brownish-black.
Properties
Magnesioferrite crystallizes as black metallic octahedral crystals. It is a magnesium iron oxide mineral, a member of the magnetite series of spinels, which forms black metallic octahedral crystals. The density is 4.6 – 4.7 (average = 4.65), and the diaphaneity is opaque. Its hardness is 6-6.5. It has a metallic luster and a dark red streak.
- Crystal habit: As octahedral crystals, massive granular
- Twinning: Twin plane {111}, contact twins
- Cleavage: On {111}
- Fracture: Uneven
- Tenacity: Brittle
- Mohs scale hardness: 6 – 6.5
- Luster: Metallic, semimetallic, dull
- Streak: Dark red
- Diaphaneity: Opaque, transparent in thin fragments
- Specific gravity: 4.55 – 4.65 measured
- Optical properties: Isotropic
Occurrence
The magnesioferrite occurs as euhedral, frequently skeletal, micron-sized octahedral crystals. It occurs in fumaroles, as a result of combustion metamorphism and coal seam fires, in glass spherules related to meteorite impacts, and as an accessory phase in kimberlites and carbonatites. Occurs as well-formed fine sized crystals or massive and granular. It has been reported from Vesuvius and Stromboli, Italy.
Association: Hematite, titanian magnetite, ferrian diopside.
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