STRUCTURE AND RAMAN SPECTROSCOPY OF A NEW MINERAL, ISOSTRUCTURAL TO LINDQUISTITE, FROM A XENOLITH OF THE OBNAZHENNAYA KIMBERLITE PIPE (KUYOKSKOYE FIELD, YAKUTSK KIMBERLITE PROVINCE)
- Authors: Butvina V., Vorobey S., Spivak A., Rashchenko S., Volkova E., Garanin V., Sharygin I., Aranovich L., Shatskiy A., Safonov O.
- Issue: Vol 523, No 2 (2025)
- Section: MINERALOGY
- Submitted: 07.05.2025
- Accepted: 12.05.2025
- Published: 11.06.2025
- URL: https://bakhtiniada.ru/2686-7397/article/view/290733
- ID: 290733
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Abstract
The structure of a new mineral, isostructural to lindquistite, with the idealized crystal chemical formula (K, Ba)Fe3+(Mg,Fe)4(Al,Cr3+,Ti4+)13O27, has been studied by single-crystal X-ray diffraction analysis. This mineral was identified in a polyphase inclusion in alumochromite from a garnet-spinel lherzolite xenolith from the Obnazhennaya kimberlite pipe (Kuyokskoe field, Yakutsk kimberlite province).
The parameters of the hexagonal cell were obtained: a = 5.81093(15) Å, b = 5.81093(15) Å, c= 32.2003(10) Å, Ve.i. = 941.63(4) Å3, pr. gr. P63/mmc, Z = 2. The structure of the mineral is layered of a mixed type. It can be described as a sequence of 14 cubic and hexagonal densely packed layers formed by oxygen atoms.
In each 7th layer, large cations X (K+ and Ba2+) are placed in 1/4 oxygen positions, which occupy position 2b and are surrounded by 12 oxygen atoms. O2- and X ions having close radii form the densest packing, while T (Mg2+, Fe2+), M (Al3+, Cr3+, Ti4+), and A (Fe3+) ions occupy voids. It was found that the new mineral is isostructural to the minerals lindquistite and hexaferrite of the W-type.
The decoding of the mineral structure as a polytypic magnetoplumbite does not reflect the reversal of the layers. The data obtained can be used to justify the identification of a separate lindquistite group, since the new mineral studied in this work is the second find in this group.
About the authors
Valentina Butvina
Author for correspondence.
Email: valkil@yandex.ru
Russian Federation
Sofia Vorobey
Email: vorobey.sofya93@mail.ru
Anna Spivak
Email: spivak@iem.ac.ru
Sergey Rashchenko
Email: rashchenko@igm.nsc.ru
Elena Volkova
Email: volkova@geol.msu.ru
Viktor Garanin
Email: vgaranin@mail.ru
Igor Sharygin
Email: isharygin@crust.irk.ru
Leonid Aranovich
Email: lyaranov@igem.ru
Anton Shatskiy
Email: shatskiyantonf@gmail.com
Oleg Safonov
Email: oleg@iem.ac.ru
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