FLUORNATROMICROLITE, (Na,Ca,Bi)2Ta2O6F, A NEW MINERAL SPECIES FROM QUIXABA, PARAIBA, BRAZIL

Witzke, Thomas; Steins, M.; Doering, Th.; Schuckmann, Walter; Wegner, Reinhard; Pöllmann, Herbert

doi:10.3749/canmin.49.4.1105

Cited by 14 publications

(3 citation statements)

References 9 publications

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“…Fluornatromicrolite (Witzke et al, 2011), (Na, #) 2 Ta 2 O 6 F, Fd3m, a 10.4451 (2) Å, V 1139.56 Å 3 . IMA number: 1998-018.…”

Section: Microlite Groupunclassified

Pyrochlore-Supergroup Minerals Nomenclature: An Update

Atencio

2021

Front. Chem.

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The general formula of the pyrochlore-supergroup minerals is A2B2X6Y. The mineral names are composed of two prefixes and one root name (identical to the name of the group). The first prefix refers to the dominant anion (or cation or H2O or vacancy) of the dominant valence at the Y-site. The second prefix refers to the dominant cation of the dominant valence [or H2O or vacancy] at the A-site. Thirty-one pyrochlore-supergroup mineral species are currently distributed into four groups [pyrochlore (B = Nb, X = O), microlite (B = Ta, X = O), roméite (B = Sb5+, X = O), and elsmoreite (B = W, X = O)] and two unassigned members [hydrokenoralstonite (B = Al, X = F) and fluornatrocoulsellite (B = Mg, X = F)]. However, when the new nomenclature system of this supergroup was introduced (2010) only seven mineral species, namely, oxycalciopyrochlore, hydropyrochlore, hydroxykenomicrolite, oxystannomicrolite, oxystibiomicrolite, hydroxycalcioroméite, and hydrokenoelsmoreite, were valid. The seven species belong to the cubic crystal system and space group Fd3¯m and O is predominant in the X structural site. The 24 new mineral species described between 2010 and 2021 are cesiokenopyrochlore, fluorcalciopyrochlore, fluornatropyrochlore, hydrokenopyrochlore, hydroxycalciopyrochlore, hydroxynatropyrochlore, hydroxykenopyrochlore, hydroxymanganopyrochlore, hydroxyplumbopyrochlore, fluorcalciomicrolite, fluornatromicrolite, hydrokenomicrolite, hydroxycalciomicrolite, kenoplumbomicrolite, oxynatromicrolite, oxycalciomicrolite, oxybismutomicrolite, fluorcalcioroméite, hydroxyferroroméite, oxycalcioroméite, oxyplumboroméite, fluornatrocoulsellite, hydrokenoralstonite, and hydroxykenoelsmoreite. Among the new species, hydroxycalciomicrolite belongs to a different space group of the cubic system, i.e., P4232. There are also some mineral species that crystallize in the trigonal system. Hydrokenoelsmoreite occurs as 3C (Fd3¯m) and 6R (R3¯) polytypes. Hydrokenomicrolite occurs as 3C (Fd3¯m) and 3R (R3¯m) polytypes, of which the latter corresponds to the discredited “parabariomicrolite.” Fluornatrocoulsellite crystallizes as 3R (R3¯m) polytype. Surely there are several new pyrochlore-supergroup minerals to be described.

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“…Fluornatromicrolite (Witzke et al, 2011), (Na, #) 2 Ta 2 O 6 F, Fd3m, a 10.4451 (2) Å, V 1139.56 Å 3 . IMA number: 1998-018.…”

Section: Microlite Groupunclassified

Pyrochlore-Supergroup Minerals Nomenclature: An Update

Atencio

2021

Front. Chem.

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“…The current IMA list of minerals (updated in November, 2019; ) includes nine valid species belonging to the microlite group. Three of them, hydroxykenomicrolite, oxystannomicrolite and oxystibiomicrolite have been redefined by Atencio et al (2010) from former species ‘cesstibtantite’, ‘sukulaite’ (= stannomicrolite) and ‘stibiomicrolite’, respectively, while six others were published as new species: fluorcalciomicrolite (Andrade et al , 2013a), fluornatromicrolite (Witzke et al , 2011), hydrokenomicrolite (Andrade et al , 2013b), hydroxycalciomicrolite (Andrade et al , 2017), kenoplumbomicrolite (Atencio et al , 2018) and oxynatromicrolite (Fan et al , 2016). Thus oxybismutomicrolite is the tenth member of the microlite group.…”

Section: Introductionmentioning

confidence: 99%

Oxybismutomicrolite, a new pyrochlore-supergroup mineral from the Malkhan pegmatite field, Central Transbaikalia, Russia

Kasatkin

Britvin

Peretyazhko

et al. 2020

MinMag

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Oxybismutomicrolite, ideally [(Bi3+,#)2]Σ4+Ta2O6O, where # = subordinate substituents, such as Na+, Ca2+ and vacancy (□), is a microlite-group, pyrochlore-supergroup mineral discovered at the Solnechnaya (‘Sunny’) pegmatite vein, Malkhan pegmatite field, Zabaykalskiy Kray, Central Transbaikalia, Russia. It forms rough octahedral crystals up to 1 mm across and equant grains up to 2 mm across embedded in an albite–lepidolite–elbaite complex. Other associated minerals are Bi-rich fluornatromicrolite, bismutotantalite and stibiotantalite. The new mineral is black, with resinous lustre; the streak is greyish white. It is non-fluorescent under ultraviolet light. Oxybismutomicrolite is brittle, with Mohs’ hardness of ~5. Cleavage is not observed, fracture is uneven. Dmeas. = 6.98(2) g/cm3 and Dcalc. = 7.056 g/cm3. The mineral is optically isotropic. The mean refractive index calculated from the Gladstone–Dale equation is 2.184. The infrared spectrum shows the absence of H2O molecules and OH groups. The chemical composition is (electron microprobe, wt.%): Na2O 3.45, CaO 2.88, MnO 0.31, PbO 0.76, Bi2O3 29.81, ThO2 0.18, TiO2 3.89, SnO2 1.77, Nb2O5 4.50, Ta2O5 51.08, F 1.17, O = F –0.49, total 99.31. The empirical formula, on the basis of 2 cations at the B site, is (Bi0.79Na0.68Ca0.32Mn0.03Pb0.02□0.16)Σ2.00(Ta1.42Ti0.30Nb0.21Sn0.07)Σ2.00O6.00(O0.52F0.38□0.10)Σ1.00. The crystal structure refinement (R = 0.019) gave the following data: cubic, Fd–3m, a = 10.4746(11) Å, V = 1149.2(4) Å3 and Z = 8. The eight strongest lines of the powder X-ray diffraction pattern [d, Å(I, %)(hkl)] are: 6.051(12)(111), 3.160(10)(311), 3.026(100)(222), 2.621(32)(400), 1.854(33)(440), 1.581(27)(622), 1.514(7)(444) and 1.203(7)(662). Type material is deposited in the collections of the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 5409/1.

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“…Minerals of the pyrochlore supergroup have recently attracted considerable attention and several new members of the group have been described from various world localities (Atencio et al ., 2010, 2013, 2017; Witzke et al ., 2011; Christy and Atencio, 2013; Biagioni et al ., 2013; Hålenius and Bosi, 2013; Yang et al ., 2014; Jingwu et al ., 2015; Andrade et al ., 2013, 2015, 2016; Li et al ., 2016; Fan et al ., 2016; Mills et al ., 2017). The pyrochlore-supergroup minerals are abundant in the Kovdor phoscorite-carbonatite pipe (Ivanyuk et al ., 2002, 2016; Mikhailova et al ., 2016; Kalashnikov et al ., 2016), with an economic-level concentration in the axial zone of the pipe (Epstein et al ., 1970).…”

Section: Introductionmentioning

confidence: 99%

Hydroxynatropyrochlore, (Na,Сa,Ce)₂Nb₂O₆(OH), a new member of the pyrochlore group from the Kovdor phoscorite–carbonatite pipe, Kola Peninsula, Russia

Ivanyuk

Yakovenchuk

Panikorovskii

et al. 2018

MinMag

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Hydroxynatropyrochlore, (Na,Сa,Ce)2Nb2O6(OH), is a new Na–Nb–OH-dominant member of the pyrochlore supergroup from the Kovdor phoscorite–carbonatite pipe, Kola Peninsula, Russia. It is cubic, Fd$\bar{3}$m, a = 10.3211(3) Å, V = 1099.46(8) Å3 and Z = 8 (from powder diffraction data) or a = 10.3276(5) Å, V = 1101.5(2) Å3 and Z = 8 (from single-crystal diffraction data). Hydroxynatropyrochlore is a characteristic accessory mineral of the low-carbonate phoscorite in the contact zone of the phoscorite–carbonatite pipe with host foidolite as well as in the carbonate-rich phoscorite and carbonatite of the pipe axial zone. It usually forms zonal cubic or cubooctahedral crystals (up to 0.5 mm in diameter) with irregularly shaped relics of amorphous U–Ta-rich hydroxykenopyrochlore inside. Characteristic associated minerals include rock-forming calcite, dolomite, forsterite, hydroxylapatite, magnetite and phlogopite, accessory baddeleyite, baryte, barytocalcite, chalcopyrite, chamosite–clinochlore, galena, gladiusite, juonniite, ilmenite, magnesite, pyrite, pyrrhotite, quintinite, spinel, strontianite, valleriite and zirconolite. Hydroxynatropyrochlore is pale brown, with an adamantine to greasy lustre and a white streak. The cleavage is average on {111} and the fracture is conchoidal. Mohs hardness is ~5. In transmitted light, the mineral is light brown, isotropic and n = 2.10(5) (λ = 589 nm). The calculated and measured densities are 4.77 and 4.60(5) g cm−3, respectively. The mean chemical composition determined by electron microprobe is: F 0.05, Na2O 7.97, CaO 10.38, TiO2 4.71, FeO 0.42, Nb2O5 56.44, Ce2O3 3.56, Ta2O5 4.73, ThO2 5.73, UO2 3.66, total 97.65 wt.%. The empirical formula calculated on the basis of Nb + Ta + Ti = 2 apfu is (Na1.02Ca0.73Ce0.09Th0.09 U0.05${\rm Fe}_{{\rm 0}{\rm. 02}}^{2 +} $)Σ2.00(Nb1.68Ti0.23Ta0.09)Σ2.00O6.03(OH1.04F0.01)Σ1.05. The simplified formula is (Na,Ca,Ce)2Nb2O6(OH). The mineral dissolves slowly in hot HCl. The strongest X-ray powder-diffraction lines [listed as (d in Å)(I)(hkl)] are as follows: 5.96(47)(111), 3.110(30)(311), 2.580(100)(222), 2.368(19)(400), 1.9875(6)(333), 1.8257(25)(440) and 1.5561(14)(622). The crystal structure of hydroxynatropyrochlore was refined to R1 = 0.026 on the basis of 80 unique observed reflections. The mineral belongs to the pyrochlore structure type A2B2O6Y1 with octahedral framework of corner-sharing BO6 octahedra with A cations and OH groups in the interstices. The Raman spectrum of hydroxynatropyrochlore contains characteristic bands of the lattice, BO6, B–O and O–H vibrations and no characteristic bands of the H2O vibrations. Within the Kovdor phoscorite–carbonatite pipe, hydroxynatropyrochlore is the latest hydrothermal mineral of the pyrochlore supergroup, which forms external rims around grains of earlier U-rich hydroxykenopyrochlore and separated crystals in voids of dolomite carbonatite veins. The mineral is named in accordance with the pyrochlore supergroup nomenclature.

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FLUORNATROMICROLITE, (Na,Ca,Bi)2Ta2O6F, A NEW MINERAL SPECIES FROM QUIXABA, PARAIBA, BRAZIL

Cited by 14 publications

References 9 publications

Pyrochlore-Supergroup Minerals Nomenclature: An Update

Pyrochlore-Supergroup Minerals Nomenclature: An Update

Oxybismutomicrolite, a new pyrochlore-supergroup mineral from the Malkhan pegmatite field, Central Transbaikalia, Russia

Hydroxynatropyrochlore, (Na,Сa,Ce)₂Nb₂O₆(OH), a new member of the pyrochlore group from the Kovdor phoscorite–carbonatite pipe, Kola Peninsula, Russia

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FLUORNATROMICROLITE, (Na,Ca,Bi)2Ta2O6F, A NEW MINERAL SPECIES FROM QUIXABA, PARAIBA, BRAZIL

Cited by 14 publications

References 9 publications

Pyrochlore-Supergroup Minerals Nomenclature: An Update

Pyrochlore-Supergroup Minerals Nomenclature: An Update

Oxybismutomicrolite, a new pyrochlore-supergroup mineral from the Malkhan pegmatite field, Central Transbaikalia, Russia

Hydroxynatropyrochlore, (Na,Сa,Ce)2Nb2O6(OH), a new member of the pyrochlore group from the Kovdor phoscorite–carbonatite pipe, Kola Peninsula, Russia

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Hydroxynatropyrochlore, (Na,Сa,Ce)₂Nb₂O₆(OH), a new member of the pyrochlore group from the Kovdor phoscorite–carbonatite pipe, Kola Peninsula, Russia