hercynite


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hercynite

[′hərs·ən‚īt]
(mineralogy)
(Fe,Mg)Al2O4 A black mineral of the spinel group; crystallizes in the isometric system. Also known as ferrospinel; iron spinel.
References in periodicals archive ?
The occurrence of orthopyroxene and hercynite, and specific chemical composition of high-grade phases, such as a high Ti content in biotite and a high Al content in orthopyroxene, are in accordance with the other geothermobarometric estimates, which suggests the peak temperature of formation over 800[degrees]C and pressure of 5-6 kbar (Fig.
An additional x-ray diffraction spectrum showed minor peaks due to hercynite, FeO[Al.
Rather it was more likely due to a metal oxide system as that of iron, possibly including other spinels such as hercynite, in which the changes between the various coloring agents (for example, red hematite contrasted with black magnetite, or maghemite, or wustite, or some combination thereof) are reversible.
At iron melting temperatures, hercynite doesn't form as readily as it does at steel melting temperatures.
In spinel-forming refractories that are alumina-enriched, it is possible to form either hercynite or galaxite [ILLUSTRATION FOR FIGURE 3 OMITTED].
For example, aluminum-coated or killed steel used in cast iron melting will result in alumina or alumina complex mineral deposits such as hercynite (iron aluminate), mullite (silica alumina), etc.
PHOTO : CL micrograph of a buildup sample showing anorthite (yellow), corundum (red) and hercynite (black) crystals.