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Magnetite has been important in understanding the conditions under which rocks form. Magnetite reacts with oxygen to produce hematite, and the mineral pair forms a buffer that can control how oxidizing its environment is (the oxygen fugacity). This buffer is known as the hematite-magnetite or HM buffer.
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.
Jacobsite is a manganese iron oxide mineral. It is in the spinel group and forms a solid solution series with magnetite. The chemical formula is (Mn,Mg)Fe 2 O 4 or with oxidation states and substitutions: (Mn 2+,Fe 2+,Mg)(Fe 3+,Mn 3+) 2 O 4. [2] [4] Jacobsite, N'Chwaning Mines, Kuruman, Kalahari manganese fields, Northern Cape Province, South ...
Mindat.org is a non-commercial interactive online database covering minerals around the world. Originally created by Jolyon Ralph as a private project in 1993, it was launched as a community-editable website in October 2000.
Ulvöspinel forms as solid solutions with magnetite at high temperatures and reducing conditions, and grains crystallized from some basalt-gabbro magmas are rich in the ulvöspinel component. The ulvöspinel component tends to oxidize to magnetite plus ilmenite during subsolidus cooling of the host rocks, and the ilmenite so produced may form ...
Titanomagnetite is a mineral containing oxides of titanium and iron, with the formula Fe 2+ (Fe 3+,Ti) 2 O 4. It is also known as titaniferous magnetite, mogensenite, Ti-magnetite, or titanian magnetite. [1] It is part of the spinel group of minerals. The Curie temperature for titanomagnetite has been found to have a wide range of 200 to 580°C ...
Pyrolusite is a mineral consisting essentially of manganese dioxide (Mn O 2) and is important as an ore of manganese. [7] It is a black, amorphous appearing mineral, often with a granular, fibrous, or columnar structure, sometimes forming reniform crusts. It has a metallic luster, a black or bluish-black streak, and readily soils the fingers.
It is a black mineral with the typical spinel properties of crystallising in the cubic system, black streaked, infusible and insoluble in most acids. There is at least partial solid solution between trevorite and magnetite , with many magnetites from ultramafic rocks containing at least trace amounts of Ni .