TY - JOUR

T1 - Odikhinchaite, Na9Sr3[(H2O)2Na]Ca6Mn3Zr3NbSi (Si24O72)O(OH)3(CO3)·H2O, a New Eudialyte-Group Mineral from the Odikhincha Intrusion, Taimyr Peninsula, Russia

AU - Gritsenko, Yuliya D.

AU - Chukanov, N.V.

AU - Aksenov, Sergey M.

AU - Pekov, I.V.

AU - Varlamov, D.A.

AU - Pautov, L.A.

AU - Vozchikova, Svetlana A.

AU - Ksenofontov, Dmitry A.

AU - Britvin, S. N.

N1 - Funding Information: Funding: This work was performed in accordance with the state task, state registration no. ААА-А19-119092390076-7 (chemical data and crystal-chemical analysis) and was partly funded by the Russian Foundation for Basic Research, grant no. 18-29-12007-mk (IR spectroscopy, powder X-ray diffraction, and physical properties) and Russian Science Foundation, grant no. 20-77-10065 (solving and refinement of the crystal structure; crystal chemical analysis and structure description). S.N.B. acknowledges Saint-Petersburg State University for financial support, grant no. 3.42.741.2017 (in part of powder X-ray diffraction measurements).

PY - 2020/12

Y1 - 2020/12

N2 - The new eudialyte-group mineral, odikhinchaite, was discovered in a peralkaline pegmatite vein hosted by melteigite at the Odikhincha ultrabasic alkaline–carbonatite intrusion, Taimyr Peninsula, Krasnoyarsk Krai, Russia. Associated minerals are orthoclase, albite, aegirine, cancrinite, ancylite-(Ce), catapleiite, and wadeite. Odikhinchaite occurs as dense rosette-like aggregates up to 11 mm across, consisting of split lamellar individuals. The mineral is translucent to transparent, deep purple, with vitreous luster. Odikhinchaite is brittle, with uneven fracture; distinct cleavage on (001) is observed. Hardness determined by the micro-indentation method is equal to 430 kgf/mm 2; the Mohs hardness is 5. D(meas.) is 2.97(1) g·cm −3, D(calc.) is 3.04 g·cm –3. Odikhinchaite is optically uniaxial (–), ω = 1.638(2), ε = 1.630(2). The IR spectrum shows the presence of the IVMn 2+O4 polyhedra, H2O molecules and CO3 2– anions. The chemical composition is (electron microprobe, H2O determined by the modified Penfield method, CO2 determined by selection sorption of gaseous annealing products; wt%): Na2O 9.25, K2O 0.59, CaO 12.77, MnO 5.49, FeO 0.75, MgO 0.24, La2O3 0.38, Ce2O3 0.39, Nd2O3 0.15, Al2O3 0.07, SiO2 44.80, ZrO2 11.13, TiO2 0.07, Nb2O5 4.17, Cl 0.69, CO2 0.90, H2O 2.22, –O = Cl –0.16, total 99.72. The crystal structure was solved using single-crystal X-ray diffraction data. Odikhinchaite is trigonal, space group R3m; the unit-cell parameters are: a = 14.2837(2) Å, c = 30.0697(3) Å, V = 5313.04(12) Å 3. The new mineral is isostructural with other 12-layered members of the eudialyte group with the space group R3m. Its crystal chemical formula is (Z = 3): { N1(Na2.58Ca0.42) N2[Na2.37Ca0.51(H2O)0.12] N3(Sr2.00K0.45Na0.35REE0.20) N4Na3 N5[(H2O)1.8Na1.2]}{ ZZr3 M1Ca6 M2(Mn 2.49Fe 2+0.51)[ M3Nb(OH)1.82O1.18]( M4SiOH)[Si3O9]2[Si9O27]2 X1[(CO3)0.53Cl0.47] X2[(H2O)0.6(O,F)0.4] XM4(CO3)0.15. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 11.42 (64) (101), 4.309 (41) (205), 3.405 (53) (131), 3.208 (45) (208, 036), 3.167 (44) (217), 2.978 (100) (315), 2.858 (86) (404).

AB - The new eudialyte-group mineral, odikhinchaite, was discovered in a peralkaline pegmatite vein hosted by melteigite at the Odikhincha ultrabasic alkaline–carbonatite intrusion, Taimyr Peninsula, Krasnoyarsk Krai, Russia. Associated minerals are orthoclase, albite, aegirine, cancrinite, ancylite-(Ce), catapleiite, and wadeite. Odikhinchaite occurs as dense rosette-like aggregates up to 11 mm across, consisting of split lamellar individuals. The mineral is translucent to transparent, deep purple, with vitreous luster. Odikhinchaite is brittle, with uneven fracture; distinct cleavage on (001) is observed. Hardness determined by the micro-indentation method is equal to 430 kgf/mm 2; the Mohs hardness is 5. D(meas.) is 2.97(1) g·cm −3, D(calc.) is 3.04 g·cm –3. Odikhinchaite is optically uniaxial (–), ω = 1.638(2), ε = 1.630(2). The IR spectrum shows the presence of the IVMn 2+O4 polyhedra, H2O molecules and CO3 2– anions. The chemical composition is (electron microprobe, H2O determined by the modified Penfield method, CO2 determined by selection sorption of gaseous annealing products; wt%): Na2O 9.25, K2O 0.59, CaO 12.77, MnO 5.49, FeO 0.75, MgO 0.24, La2O3 0.38, Ce2O3 0.39, Nd2O3 0.15, Al2O3 0.07, SiO2 44.80, ZrO2 11.13, TiO2 0.07, Nb2O5 4.17, Cl 0.69, CO2 0.90, H2O 2.22, –O = Cl –0.16, total 99.72. The crystal structure was solved using single-crystal X-ray diffraction data. Odikhinchaite is trigonal, space group R3m; the unit-cell parameters are: a = 14.2837(2) Å, c = 30.0697(3) Å, V = 5313.04(12) Å 3. The new mineral is isostructural with other 12-layered members of the eudialyte group with the space group R3m. Its crystal chemical formula is (Z = 3): { N1(Na2.58Ca0.42) N2[Na2.37Ca0.51(H2O)0.12] N3(Sr2.00K0.45Na0.35REE0.20) N4Na3 N5[(H2O)1.8Na1.2]}{ ZZr3 M1Ca6 M2(Mn 2.49Fe 2+0.51)[ M3Nb(OH)1.82O1.18]( M4SiOH)[Si3O9]2[Si9O27]2 X1[(CO3)0.53Cl0.47] X2[(H2O)0.6(O,F)0.4] XM4(CO3)0.15. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 11.42 (64) (101), 4.309 (41) (205), 3.405 (53) (131), 3.208 (45) (208, 036), 3.167 (44) (217), 2.978 (100) (315), 2.858 (86) (404).

KW - Crystal structure

KW - Eudialyte group

KW - New mineral

KW - Odikhincha intrusion

KW - Odikhinchaite

KW - Peralkaline pegmatite

KW - Taimyr Peninsula

UR - http://www.scopus.com/inward/record.url?scp=85096797294&partnerID=8YFLogxK

U2 - 10.3390/min10121062

DO - 10.3390/min10121062

M3 - Article

VL - 10

SP - 1

EP - 15

JO - Minerals

JF - Minerals

SN - 2075-163X

IS - 12

M1 - 1062

ER -