The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part IV. Alexkuznetsovite-(La), La2Mn(CO3)(Si2O7), alexkuznetsovite-(Ce), Ce2Mn(CO3)(Si2O7) and biraite-(La), La2Fe2+(CO3)(Si2O7), three new isostructural minerals and a definition of the biraite group
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F21%3A00124486" target="_blank" >RIV/00216224:14310/21:00124486 - isvavai.cz</a>
Result on the web
<a href="https://www.cambridge.org/core/journals/mineralogical-magazine/article/mineralogy-of-the-historical-mochalin-log-ree-deposit-south-urals-russia-part-iv-alexkuznetsovitela-la2mnco3si2o7-alexkuznetsovitece-ce2mnco3si2o7-and-biraitela-la2fe2co3si2o7-three-n" target="_blank" >https://www.cambridge.org/core/journals/mineralogical-magazine/article/mineralogy-of-the-historical-mochalin-log-ree-deposit-south-urals-russia-part-iv-alexkuznetsovitela-la2mnco3si2o7-alexkuznetsovitece-ce2mnco3si2o7-and-biraitela-la2fe2co3si2o7-three-n</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1180/mgm.2021.64" target="_blank" >10.1180/mgm.2021.64</a>
Alternative languages
Result language
angličtina
Original language name
The mineralogy of the historical Mochalin Log REE deposit, South Urals, Russia. Part IV. Alexkuznetsovite-(La), La2Mn(CO3)(Si2O7), alexkuznetsovite-(Ce), Ce2Mn(CO3)(Si2O7) and biraite-(La), La2Fe2+(CO3)(Si2O7), three new isostructural minerals and a definition of the biraite group
Original language description
Three new isostructural minerals, alexkuznetsovite-(La), ideally La2Mn(CO3)(Si2O7), alexkuznetsovite-(Ce) Ce2Mn(CO3)(Si2O7) and biraite-(La) La2Fe2+(CO3)(Si2O7), were discovered in polymineralic nodules from the Mochalin Log REE deposit, South Urals, Russia. The new minerals form anhedral grains up to 0.3 mm x 0.4 mm [alexkuznetsovite-(La)], 0.5 mm x 0.9 mm [alexkuznetsovite-(Ce)] and 0.2 mm x 1.2 mm [biraite-(La)] embedded in granular aggregates consisting of different REE minerals [allanite-(Ce)/-(La), bastnasite-(Ce)/-(La), fluorbritholite-(Ce), perbOeite-(Ce)/-(La), percleveite-(Ce)/-(La) and tornebohmite-(Ce)/-(La)]. All three new species are brown to dark brown, translucent in thin fragments, with white streak, vitreous lustre and Mohs' hardness of similar to 5. D-calc = 4.713 [alexkuznetsovite-(La)], 4.687 [alexkuznetsovite-(Ce)] and 4.682 [biraite-La)] g.cm(-3). Their empirical formulae, calculated on the basis of 2 Si and 10 O apfu, are: alexkuznetsovite-(La): (La0.98Ce0.89Nd0.10Pr0.05)(Sigma 2.02)Mn0.502+Fe0.292+Ca0.12Mg0.03(CO3)(0.94)(HCO3)(0.06) (Si2O7); alexkuznetsovite-(Ce): (Ce0.96La0.78Nd0.16Pr0.07)(Sigma 1.97)Th0.01Mn0.502+Fe0.332+Ca0.14Mg0.02(CO3)(0.93)(HCO3)(0.07)(Si2O7); and biraite-(La): (La0.95Ce0.87Nd0.08Pr0.04)(Sigma 1.94)Th0.01Ca0.12Fe0.442+Mn0.382+Mg0.07(CO3)(0.88)(HCO3)(0.12)(Si2O7). The new minerals are monoclinic, P2(1)/c and Z = 4. The unit-cell parameters of alexkuznetsovite-(La)/alexkuznetsovite-(Ce)/biraite-(La) are: a = 6.5642(3)/6.5764(4)/6.5660(10), b = 6.7689(3)/6.7685(4)/6.7666(11), c = 18.7213(10)/18.7493(15)/18.698(3) angstrom, beta = 108.684(6)/108.672(8)/108.952(16)degrees and V = 788.00(7)/790.66(10)/785.7(2) angstrom(3). The crystal structures are solved from single-crystal X-ray diffraction data; R = 0.0628 [alexkuznetsovite-(La)], 0.0589 [alexkuznetsovite-(Ce)] and 0.1193 [biraite-(La)]. A new biraite group is defined; it includes isostructural biraite-(Ce) and the three new minerals described herein. The rootname alexkuznetsovite is given in honour of the Russian mineral collector Alexey M. Kuznetsov (born 1962) who provided samples in which all three new minerals were found. The Levinson's suffix-modifier -(La) or -(Ce) indicates the predominance of La or Ce among REE in the mineral. Biraite-(La) is named as an analogue of biraite-(Ce) with La prevailing among REE.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10504 - Mineralogy
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2021
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Mineralogical Magazine
ISSN
0026-461X
e-ISSN
1471-8022
Volume of the periodical
85
Issue of the periodical within the volume
5
Country of publishing house
GB - UNITED KINGDOM
Number of pages
12
Pages from-to
772-783
UT code for WoS article
000723015700012
EID of the result in the Scopus database
2-s2.0-85112363418