naa a22 4500 510736254 CHVBK 20180411083011.0 cr unu---uuuuu 180411e20131201xx s 000 0 eng 10.1134/S1075701513070076 doi (NATIONALLICENCE)springer-10.1134/S1075701513070076 Davinciite, Na12K3Ca6Fe 3 2+ Zr3(Si26O73OH)Cl2, a New K,Na-Ordered mineral of the eudialyte group from the Khibiny Alkaline Pluton, Kola Peninsula, Russia [Elektronische Daten] [A. Khomyakov, G. Nechelyustov, R. Rastsvetaeva, K. Rozenberg] This paper presents a description of a new zirconosilicate of the eudialyte group, which was named davinciite in honor of Leonardo da Vinci (1452-1519), a famous Italian scientist, painter, sculptor and architect. The new mineral has been found in hyperagpaitic pegmatite at the Rasvumchorr Mountain, Khibiny Pluton, Kola Peninsula, as relict inclusions, up to 1-2 mm in size in a rastsvetaevite matrix. It is associated with nepheline, sodalite, potassium feldspar, delhayelite, aegirine, shcherbakovite, villiaumite, nitrite, nacaphite, rasvumite, and djerfisherite. Davinciite is dark lavender and transparent, with a vitreous luster and white streak. The new mineral is brittle, with conchoidal fracture; the Mohs' hardness is 5. No indications of cleavage or parting were observed. The measured density is 2.82(2) g/cm3 (volumetric method); the calculated density is 2.848 g/cm3. Davinciite is optically uniaxial, positive; ω = 1.603(2), ɛ = 1.605(2). It is nonpleochroic and nonfluorescent in UV light. The new mineral slowly breaks down and gelates in 50% HCl and HNO3. It is trigonal, space group R3m. The unit-cell dimensions are a = 14.2956(2), c = 30.0228(5) Å, V=5313.6(2) Å3. The strongest reflections in the X-ray powder diffraction pattern [d, Å (I, %) (hkl)] are as follows: 2.981(100)(315), 2.860(96)(404), 4.309(66)(205), 3.207(63)(208), 6.415(54)(104), 3.162(43)(217). The chemical composition (electron microprobe, H2O calculated from X-ray diffraction data) is as follows, wt %: 12.69 Na2O, 3.53 K2O, 11.02 CaO, 0.98 SrO, 0.15 BaO, 5.33 FeO, 0.37 MnO, 0.07 Al2O3, 51.20 SiO2, 0.39 TiO2, 11.33 ZrO2, 0.21HfO2, 0.09 Nb2O5, 1.89 Cl, 0.93H2O, -O = Cl2 0.43; total is 99.75. The empirical formula calculated on the basis of Si + Al + Zr + Hf + Ti + Nb = 29 (Z = 3) is (Na1l.75Sr0.29Ba0.03)Σ12.07(K2.28Na0.72)Σ3Ca5.99(Fe2.26Mn0.16)Σ2.42(Zr2.80Ti0.15Hf0.03Nb0.02) Σ3(Si1.96Al0.04)Σ2[Si3O9]2 [Si9O27]2[(OH)1.42O0.58]Σ2[Cl1.62(H2O)0.38]Σ2 · 0.48H2O. The simplified formula is Na12K3Ca6Fe 3 2+ Zr3(Si26O73OH)Cl2. The IR-spectrum is given and the crystal structure is described. The position of davinciite in the crystal chemical taxonomy of the eudialyte group is shown, and its relationships with the other eudialyte-group minerals (acentric eudialyte, andrianovite, and kentbrooksite) are characterized. The type material of davinciite is deposited in the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow. Pleiades Publishing, Ltd., 2013 Khomyakov A. Institute of Mineralogy, Geochemistry, and Crystal Chemistry of Rare Elements, ul. Veresaeva 15, 121357, Moscow, Russia aut Nechelyustov G. All-Russia Institute of Mineral Resources, Staromonetnyi per. 31, 109017, Moscow, Russia aut Rastsvetaeva R. Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, 117333, Moscow, Russia aut Rozenberg K. Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, 117333, Moscow, Russia aut Geology of Ore Deposits Springer US; http://www.springer-ny.com 55/7(2013-12-01), 532-540 1075-7015 55:7<532 2013 55 11477 https://doi.org/10.1134/S1075701513070076 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1134/S1075701513070076 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Khomyakov A. Institute of Mineralogy, Geochemistry, and Crystal Chemistry of Rare Elements, ul. Veresaeva 15, 121357, Moscow, Russia aut NATIONALLICENCE 700 1- Nechelyustov G. All-Russia Institute of Mineral Resources, Staromonetnyi per. 31, 109017, Moscow, Russia aut NATIONALLICENCE 700 1- Rastsvetaeva R. Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, 117333, Moscow, Russia aut NATIONALLICENCE 700 1- Rozenberg K. Institute of Crystallography, Russian Academy of Sciences, Leninskii pr. 59, 117333, Moscow, Russia aut NATIONALLICENCE 773 0- Geology of Ore Deposits Springer US; http://www.springer-ny.com 55/7(2013-12-01), 532-540 1075-7015 55:7<532 2013 55 11477 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer