J 2018

Gadolinite-(Nd), a new member of the gadolinite supergroup from Fe-REE deposits of Bastnas-type, Sweden

ŠKODA, Radek; J. PLÁŠIL; Renata ČOPJAKOVÁ; Milan NOVÁK; E. JONSSON et al.

Základní údaje

Originální název

Gadolinite-(Nd), a new member of the gadolinite supergroup from Fe-REE deposits of Bastnas-type, Sweden

Autoři

Vydání

Mineralogical Magazine, Middlesex, Mineralogical Society, 2018, 0026-461X

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10504 Mineralogy

Stát vydavatele

Velká Británie a Severní Irsko

Utajení

není předmětem státního či obchodního tajemství

Odkazy

Impakt faktor

Impact factor: 2.210

Označené pro přenos do RIV

Ano

Kód RIV

RIV/00216224:14310/18:00101804

Organizační jednotka

Přírodovědecká fakulta

EID Scopus

Klíčová slova anglicky

gadolinite-(Nd); rare-earth elements; new mineral; crystal structure; Malmkarra; Bastnas-type deposits
Změněno: 23. 4. 2024 14:41, Mgr. Michal Petr

Anotace

V originále

A new member of the gadolinite supergroup, gadolinite-(Nd), IMA2016-013, ideally Nd2FeBe2Si2O10, was found in the Malmkarra mine, similar to 3.5km WSW of Norberg, south-central Sweden, where it occurs in association with fluorbritholite-(Ce), vastmanlandite-(Ce), dollaseite-(Ce), bastnasite-(Ce) and tremolite. Gadolinite-(Nd) forms anhedral grains up to 150 mu m in size, commonly occurring as aggregates of olive green colour. The crystals are transparent with vitreous to adamantine lustre. Gadolinite-(Nd) is brittle with conchoidal fracture, no cleavage or parting was observed. It has a white streak, the Mohs hardness is 6.5-7 and the calculated density is 4.86gcm(-3). Optically, the mineral is weakly pleochroic in shades of olive green, biaxial (-), n=1.78(1), n((calc.))=1.80, n=1.81(1) measured in white light, 2V((meas.))=62(3)degrees. Electron-microprobe and laser ablation inductively coupled plasma mass spectrometry analysis [in wt.%] provided SiO2 21.77, Y2O3 5.49, La2O3 2.78, Ce-2 O-3 14.04, Pr2O3 3.28, Nd2O3 19.27, Sm2O3 5.30, Eu2O3 0.24, Gd2O3 4.10, Tb2O3 0.36, Dy2O3 1.32, Ho2O3 0.18, Er2O3 0.38, MgO 0.51, CaO 0.14, MnO 0.10, FeO 10.62, B2O3 0.10, BeOcalc. 8.99, H2Ocalc. 0.55 and total 99.52 giving the following empirical formula (based on 2 Si): (Nd0.632Ce0.472Y0.268Sm0.168Gd0.125Pr0.110La0.094Dy0.039Ca0.014Er0.011Tb0.011Eu0.008Ho0.008)(Sigma 1.957)(Fe0.816Mg0.070Mn0.008)(Sigma 0.894)(Be1.984B0.016)(Sigma 2.000)Si2O9.660OH0.337. A weak Raman vibration band at similar to 3525cm(-1) confirms the presence of water in the structure. Gadolinite-(Nd) is monoclinic, P2(1)/c, with a=4.8216(3) angstrom, b=7.6985(4) angstrom, c=10.1362(6) angstrom, beta =90.234(4)degrees, V=376.24(6) angstrom(3) and Z=2. The strongest X-ray diffraction lines are [d(obs) in angstrom (hkl) I-rel]: 4.830 (100) 72, 3.603 (021) 37, 3.191(-112) 52, 3.097 (013) 35, 2.888 (121) 100, 2.607(113) 49, 2.412 (200) 24. Along with the Malmkarra mine, gadolinite-(Nd) was also recorded also at Johannagruvan and Nya Bastnas. The minerals of the gadolinite subgroup together with fluorbritholite-(Ce) incorporate the highest fraction of medium-to-heavy rare-earth elements among associated rare-earth element minerals in the Malmkarra mine and possibly in all Bastnas-type deposits.

Návaznosti

GA14-13347S, projekt VaV
Název: Variabilita lehkých prvků (Li, Be, B) ve vybraných horninotvorných a akcesorických minerálech z felsických magmatických a metamorfovaných hornin
Investor: Grantová agentura ČR, Variabilita lehkých prvků (Li, Be, B) ve vybraných horninotvorných a akcesorických minerálech z felsických magmatických a metamorfovaných hornin