Clarification of status of species in the pyrochlore supergroup

Christy, Andrew G.; Atencio, Daniel

doi:10.1180/minmag.2013.077.1.02

Cited by 55 publications

(40 citation statements)

References 12 publications

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“…This generally inhomogeneous weathering product appears to be microcrystalline but may in part be amorphous. According to the observed stoichiometry, crystalline forms probably belong, at least in part, to the roméite group of oxides, which itself belongs to the large pyrochlore supergroup of minerals (Atencio et al 2010, Christy & Atencio 2013. The general formula of the pyrochlore supergroup is [8]…”

Section: Secondary Mineralsmentioning

confidence: 99%

Mineralogy and Weathering of Realgar-Rich Tailings At a Former As-Sb-Cr Mine At Lojane, North Macedonia

Đorđević

Kolitsch

Serafimovski

et al. 2019

The Canadian Mineralogist

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In the Lojane area (North Macedonia) ores of Sb (stibnite), As (realgar), and Cr (chromite) were mined and processed in a metallurgical plant until 1979. Over one million tons of flotation tailings containing As, Sb, and other hazardous substances are located in an open dump site for flotation waste created by the mine. The tailings site is completely unprotected, and its orange color reflects a very high concentration of arsenic (fine-grained realgar superficially altered to pararealgar). In order to better understand the weathering behavior of these tailings, which is necessary to evaluate the environmental risks (mainly from the mobilization of As-Sb-Cr), solid waste material was sampled and studied from the chemical and mineralogical point of view. The material was characterized by inductively coupled plasma-mass spectrometry (ICP-MS), inductively coupled plasmaoptical emission spectrometry (ICP-OES), X-ray diffraction analysis (both single crystal and powder), scanning electron microscopy (SEM) with energy-dispersive microanalysis (EDX), Raman spectroscopy, and transmission electron microscopy (TEM) with selected area electron diffraction (SAED), energy-dispersive X-ray analysis (EDX), and electron energy loss spectrometry (EELS). The studied tailings material is comprised mostly of well-crystallized realgar, gypsum, and quartz, and minor amounts of stibnite, pararealgar, chromite, and sulfur. Very minor pyrite is found within quartz aggregates. The most abundant secondary phase, which forms thin coatings around realgar and stibnite grains, is an As-Sb-Fe-Ca-(Ni)-oxide/ hydroxide in which the As:Sb ratio varies from ca. 2:1 to 1:2.2 and Fe contents are variable.

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Section: Secondary Mineralsmentioning

confidence: 99%

Mineralogy and Weathering of Realgar-Rich Tailings At a Former As-Sb-Cr Mine At Lojane, North Macedonia

Đorđević

Kolitsch

Serafimovski

et al. 2019

The Canadian Mineralogist

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“…They are common accessory phases in carbonatite and are often found in such lithologies as nepheline syenite, alkaline gabbro and granitoids, pegmatite, and in albite and greisen granites [1][2][3][4][5][6][7][8]. Pyrochlore minerals have diverse compositions with the general formula A 2−m B 2 O 6−w Y 1−n , where A represents large cations (Na, Ca, U, Th, REE, Y, Sr, Ba, Pb, Sn, and H 2 O) and site vacancies, the B-site is occupied by smaller cations (Nb, Ti, and Ta), and Y is occupied by F, OH − , O 2− , and H 2 O or site vacancies [9][10][11]. The symbols m, w, and n represent parameters indicating incomplete occupancy of the A, X, and Y.…”

Section: Introductionmentioning

confidence: 99%

Pyrochlore-Group Minerals in the Granite-Hosted Katugin Rare-Metal Deposit, Transbaikalia, Russia

et al. 2019

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Pyrochlore group minerals are the main raw phases in granitic rocks of the Katugin complex-ore deposit that stores Nb, Ta, Y, REE, U, Th, Zr, and cryolite. There are three main types: Primary magmatic, early postmagmatic (secondary-I), and late hydrothermal (secondary-II) pyrochlores. The primary magmatic phase is fluornatropyrochlore, which has high concentrations of Na2O (to 10.5 wt.%), F (to 5.4 wt.%), and REE2O3 (to 17.3 wt.%) but also low CaO (0.6–4.3 wt.%), UO2 (to 2.6 wt.%), ThO2 (to 1.8 wt.%), and PbO (to 1.4 wt.%). Pyrochlore of this type is very rare in nature and is limited to a few occurrences: Rare-metal deposits of Nechalacho in syenite and nepheline syenite (Canada) and Mariupol in nepheline syenite (Ukraine). It may have crystallized synchronously with or slightly later than melanocratic minerals (aegirine, biotite, and arfvedsonite) at the late magmatic stage when Fe from the melt became bound, which hindered the crystallization of columbite. Secondary-I pyrochlore follows cracks or replaces primary pyrochlore in grain rims and is compositionally similar to the early phase, except for lower Na2O concentrations (2.8 wt.%), relatively low F (4 wt.%), and less complete A- and Y-sites occupancy. Secondary-II pyrochlore is a product of late hydrothermal alteration, which postdated the formation of the Katugin deposit. It differs in large ranges of elements and contains minor K, Ba, Pb, Fe, and significant Si concentrations but also low Na and F. Its composition mostly falls within the field of hydro- and keno-pyrochlore.

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“…The description of fluornatropyrochlore (IMA 2013-056), with a general formulae (Na,Pb,Ca,REE,U) 2 Nb 2 O 6 F changes status of this mineral from possible new species (Christy and Atencio 2013) to an officially approved species according current nomenclature of the pyrochlore supergroup (Atencio et al 2010). The mineral was found in the alkali granite intruded into Silurian marble at the Boziguoer REE deposit, Baicheng County, Akesu, Xinjiang Autonomous Region, China (42°13′14″N; 81°54′29″E).…”

Section: Ferromerrillite*mentioning

confidence: 99%

New Mineral NamesAlfredopetroviteBussyite-(Y)ColinowensiteEsquireiteFerromerrilliteFluornatropyrochloreFluor-SchorlHogarthiteShiloviteTapiaiteWaimirite-(Y)

Belakovskiy

Cámara

Gagné

2016

American Mineralogist

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Alfredopetrovite (IMA 2015-026), ideally Al 2 (Se 4+ O 3) 3 •6H 2 O, is a new selenite mineral from the El Dragόn mine, Antonio Quijarro Province, Potosí Department, Bolivia. The mine exploited a telethermal deposit consisting of a single selenide vein hosted by sandstones and shales. The main primary mineral is a Co-rich krut'aite-penroseite. Clausthalite, petrovicite, watkinsonite, eldragόnite, and grundmannite were crystallized from later solutions. Alfredopetrovite is a secondary mineral and occurs in vugs in a krut'aite-penroseite-dolomite-goethite matrix. Other closely associated secondary minerals are: ahlfeldite, allophane, calcite, chalcomenite, favreauite, felsőbányaite, malachite, and molybdomenite. Alfredopetrovite forms colorless to blue (transmit chalcomenite color) drusy/scaly coatings and compact balls up to 0.5 mm. Individual crystals are up to ~0.1 mm. Crystals are transparent with a white streak and a vitreous luster. The mineral is brittle with a smooth curved fracture and no apparent cleavage. Mohs hardness is 2½. The density was not measured because crystal fragments are virtually invisible in density liquids; D calc = 2.504 g/cm 3. Alfredopetrovite is optically uniaxial (+), ω = 1.554(2), and ε = 1.566(2) (white light); non-pleochroic. The average of 3 electron probe WDS analyses [wt% (range)

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Clarification of status of species in the pyrochlore supergroup

Cited by 55 publications

References 12 publications

Mineralogy and Weathering of Realgar-Rich Tailings At a Former As-Sb-Cr Mine At Lojane, North Macedonia

Mineralogy and Weathering of Realgar-Rich Tailings At a Former As-Sb-Cr Mine At Lojane, North Macedonia

Pyrochlore-Group Minerals in the Granite-Hosted Katugin Rare-Metal Deposit, Transbaikalia, Russia

New Mineral NamesAlfredopetroviteBussyite-(Y)ColinowensiteEsquireiteFerromerrilliteFluornatropyrochloreFluor-SchorlHogarthiteShiloviteTapiaiteWaimirite-(Y)

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