gahnite


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gahnite

[′gä‚nīt]
(mineralogy)
ZnAl2O4 A usually dark-green, but sometimes yellow, gray, or black spinel mineral consisting of an oxide of zinc and aluminum. Also known as zinc spinel.
References in periodicals archive ?
it often provides the other oxide partner in mineral complexes, such as magnesia/alumina spinel, calcium aluminate, iron alumina spinel (hercynite) and zinc alumina spinel (gahnite).
These include: annabergite, aragonite, argentopentlandite (Sirka, 1988), brochantite, chlorite (group), covellite, devilline, erythrite, gadolinite, gahnite, goethite, gold-silver (electrum), illite, kaolinite, langite, malachite, montmorillonite, natrojarosite, naumannite (Frigstad, 1972), palygorskite, posnjakite, scheelite, sepiolite (van der Wel, 1972), stilpnomelane, sulfur, tetrahedrite and tremolite-actinolite.
Associated minerals are: quartz, magnetite, spessartine-rich garnet, "apatite," sillimanite, ferroan gahnite, sulfides, Mn-rich grunerite (in places manganogrunerite), manganoan fayalite and Mn-rich pyroxferroite.
The type material (Greece) is from an emery and is associated with: corundum (partly altered to diaspore), chloritoid, Ti-rich hematite, ilmenite, gahnite, "tourmaline," rutile, and calcite.
The mineral is stated to occur as epitactic overgrowths on gahnite crystals with [001] of zincohogbomite parallel to [111] of gahnite.
Probe standards are as follows: cobaltite (As); gahnite (Zn); spessartine (Mn); forsterite (Mg); fayalite (Fe); kyanite (Al).
The following standards were used: Cd: Cd metal; Cu: olivenite; As: cobaltite; K: orthoclase; Ca: diopside; Mn: spessartine; Zn: gahnite. Data were reduced using the [Phi][Rho]Z method of Pouchou and Pichoir (1985).
Subhedral green grains and blebs of gahnite in granular sulfides have been identified by EDS and optical analysis (George Robinson, pers.
Additional minerals present include zircon, gahnite, minor spessartine, hectorite and coronadite, and secondary phosphates fluorapatite, eosphorite and crandallite.