Rare-Element Mineralogy of the Uzumine Granitic Pegmatite, Abukuma Mountains, Northeastern Japan

Nakajima, Tsunehiko; Kurosawa, Masanori

doi:10.2113/gscanmin.44.1.31

Cited by 9 publications

(1 citation statement)

References 24 publications

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“…A mineral with the empirical formula [REE 0.52 (U,Th) 0.25 (Fe 2+ , Mn,Ca) 0.20 ] Σ0.97 [(Nb,Ta) 1.26 Fe 3+ 0.43 (Ti,Zr,Sn,Hf) 0.28 W 0.03 ]O 6 and with Y as the predominant REE was described by Nakajima and Kurosawa (2006) as 'euxenite'. If this sample is isostructural with euxenite, its end-member formula should be Y(Nb 1.5 Fe 3+ 0.5 ) O 6 .…”

Section: Insufficiently Studied Mineralsmentioning

confidence: 99%

Columbite supergroup of minerals: nomenclature and classification

Чуканов

Pasero

Aksenov

et al. 2022

MinMag

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The columbite supergroup is established. It includes five mineral groups (ixiolite, wolframite, samarskite, columbite, and wodginite) and one ungrouped species (lithiotantite). The criteria for a mineral to belong to the columbite supergroup are: the general stoichiometry MO2; the crystal structure based on the hexagonal close packing (hcp) of anions (or close to it); the six-fold coordination number of M-type cations (augmented to eight-fold in the case of slight distortion of hcp); and the presence of zig-zag chains of edge-sharing M-centered polyhedra. The ixiolite-type structure is considered as an aristotype with the space group Pbcn, the smallest unit cell volume, and the basic vectors a0, b0, c0. Based on the multiplying of the ixiolite-type unit cell the following derivatives are distinguished: ixiolite type (ixiolite-group minerals; a = a0, b = b0, c = c0; Pbcn; the members are ixiolite-(Mn 2+ ), ixiolite-(Fe 2+ ), scrutinyite, seifertite, and srilankite), wolframite type (wolframite-group minerals, ordered analogs of the ixiolite type with a = a0, b = b0, c = c0; P2/c; the members are ferberite, hübnerite, huanzalaite, sanmartinite, heftetjernite, nioboheftetjernite, rossovskyite, and andriesite), samarskite type (samarskite-group minerals; a = 2a0, b = b0, c = c0; P2/c; the members are samarskite-(Y), ekebergite, and shakhdaraite-(Y)), columbite type (columbite-group minerals; a = 3a0, b = b0, c = c0; Pbcn; the members are columbite-(Fe), columbite-(Mn), columbite-(Mg), tantalite-(Fe), tantalite-(Mn), tantalite-(Mg), fersmite, euxenite-(Y), tanteuxenite-(Y), and uranopolycrase), and wodginite type (wodginite-group minerals; a = 2a0, b = 2b0, c = c0; C2/c; the members are wodginite, ferrowodginite, titanowodginite, ferrotitanowodginite, tantalowodginite, lithiowodginite, and achalaite). Samarskite-(Yb), ishikawaite, and calciosamarskite are insufficiently studied minerals tentatively considered as possible members of the samarskite supergroup. Qitianlingite, yttrocolumbite-(Y), yttrotantalite-(Y), and yttrocrasite-(Y) are questionable minerals which need further studies. Polycrase-(Y) is discredited as a mineral identical with euxenite-(Y). Ixiolite has been renamed to ixiolite-(Mn 2+ ),with the end-member formula (Ta2/3Mn 2+ 1/3)O2. Ta-and Nb-dominant analogues of ixiolite with different schemes of charge balancing have the end-member formulae (M1 5+ 0.5M2 3+ 0.5)O2,

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Section: Insufficiently Studied Mineralsmentioning

confidence: 99%