magnesioferrite

Magnesioferrite is a magnesium iron oxide mineral, a member of the magnetite series of spinels. Magnesioferrite crystallizes as black metallic octahedral crystals. It is named after its chemical composition of magnesium and ferric iron. The density is 4.6 - 4.7 (average = 4.65), and the diaphaniety is opaque. Occurs as well-formed fine sized crystals or massive and granular. Its hardness is 6-6.5. It has a metallic luster and a dark red streak.

Key facts

Mineral.name: Magnesioferrite
Mineral.image: Magnesioferrite - Ochtendung, Eifel, Germany.jpg
Mineral.imagesize: 260px
Mineral.caption: Magnesioferrite from Ochtendung, Eifel, Germany
Mineral.category: Oxide minerals Spinel group Spinel structural group
Mineral.formula: Mg(Fe3+)2O4
Mineral.IMAsymbol: Mfr
Mineral.strunz: 4.BB.05
Mineral.system: Cubic
Mineral.class: Hexoctahedral (mm) H-M symbol: (4/m 2/m)
Mineral.symmetry: Fdm
Mineral.unit cell: a = 8.3866 Å; Z = 8
Mineral.color: Black to brownish black
Mineral.habit: As octahedral crystals, massive granular
Mineral.twinning: Twin plane , contact twins
Mineral.cleavage: On
Mineral.fracture: Uneven
Mineral.tenacity: Brittle

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Occurrence
References

==Occurrence== It occurs in fumaroles, as a result of combustion metamorphism and coal seam fires, in glass spherules related to meteorite impacts, and as accessory phase in kimberlites and carbonatites.

Excerpted from Wikipedia’s “magnesioferrite” article, available under the CC BY-SA 4.0 licence.