A New Mineral from Poзos De Caldas, Minas Gerais

Home , Eudialyte group, Kentbrooksite, Quetzalcoatlite, Tlalocite, Utahite

Ñïèñîê ëèòåðàòóðû

Ïåêîâ È. Â., Âèíîãðàäîâà Ð. À., ×óêàíîâ Í. Â., Êóëèêîâà È. Ì. Î ìàãíåçèàëüíûõ è êîáàëüòîâûõ àð- ñåíàòàõ ãðóïï ôàéðôèëäèòà è ðîçåëèòà / ÇÂÌÎ. 2001. ¹ 4. Ñ. 10—23. 4+ Burns P. C., Clark C. M., Gault R. A. Juabite, CaCu10(Te O3)4(AsO4)4(OH)2(H2O)4: crystal structure and revision of the chemical formula / Canad. Miner. 2000a. Vol. 38. P. 823—830. Burns P. C., Pluth J. J., Smith J. V., Eng P., Steele I., Housley R. M. Quetzalcoatlite: A new octahedral-tetrahedral structure from a 2 % 2 % 40 ìm3 crystal at the Advances Photon Source-GSE-CARS Facility / Amer. Miner. 2000b. Vol. 85. P. 604—607. 4+ 6+ Frost R. L., Keefe E. C. Raman spectroscopic study of kuranakhite PbMn Te O6 — a rare tellurate mineral / J. Raman Spectroscopy. 2009. Vol. 40(3). P. 249—252. Grice J. D., Roberts A. C. Frankhawthorneite, a unique HCP framework structure of a cupric tellurate / Canad. Miner. 1995. Vol. 33. P. 823—830. Lam A. E., Groat L. A., Ercit T. S. The crystal structure of dugganite, Pb3Zn3TeAs2O14 / Canad. Miner. 1998. Vol. 36. P. 823—830. Mandarino J. A. The Gladstone—Dale relationship: Part IV. The compatibility concept and its applicati- on / Canad. Miner. 1981. Vol. 19. P. 441—450. Pekov I. V., Jensen M. C., Roberts A. C., Nikischer A. J. A new mineral from an old locality: eurekadum- pite takes seventeen years to characterize / Mineral News. 2010. Vol. 26(2). P. 1—3. Pertlik F. Der Strukturtyp von Emmonsit, {Fe2(TeO3)3$H2O}$xH2O(x = 0—1) / Tschermaks Miner. Petrog. Mitt. 1972. Vol. 18. P. 157—168. Roberts A., Stirling J. A. R., Criddle A. J., Jensen M. C., Moffatt E. A., Wiulson W. E. Utahite, a new mineral and associated copper tellurates from the Centennial Eureka mine, Tintic district, Juab County, Utah / Miner. Record. 1997. Vol. 27. P. 175—179. Roberts A. C. An orthorhombic cell for tlalocite / Geol. Surv. Can. 1978. Paper 78—1C. P. 104. Shannon R. D., Prewitt C. T. Effective ionic radii in oxides and fluorides / Acta Cryst. 1969. C25. P. 925—945. Williams S. Quetzalcoatlite, Cu4Zn8(TeO3)3(OH)18, a new mineral from Moctezuma, Sonora / Miner. Mag. 1973. Vol. 39. P. 261—263. Williams S. Xocomecatlite, Cu3TeO4(OH)18, and tlalocite, Cu10Zn6(TeO3)(TeO4)2Cl(OH)25$27H2O, two new minerals from Moctezuma, Sonora, Mexico / Miner. Mag. 1975. Vol. 40./ P. 221—226. Ïîñòóïèëà â ðåäàêöèþ 26 ôåâðàëÿ 2010 ã.

ÓÄÊ 549.657+548.6 ÇÐÌÎ, ¹ 4, 2010 ã. Zapiski RMO, N 4, 2010

S. F. NOMURA,* D. ATENCIO,* N. V. CHUKANOV,** R. K. RASTSVETAEVA,*** J. M. V. COUTINHO,* T. K. KARIPIDIS*** MANGANOEUDIALYTE — A NEW MINERAL FROM POÇOS DE CALDAS, MINAS GERAIS, BRAZIL

* Instituto de Geociências, Universidade de São Paulo, Rua do Lago, 562, 05508-080, São Paulo, SP, Brazil; e-mail: [email protected] ** Institute of Problems of Chemical Physics, 142432 Chernogolovka, Moscow Oblast, Russia *** Institute of Crystallography, Russian Academy of Sciences, Leninskii Prospeñt 59, Moscow 119333, Russia

Manganoeudialyte, ideally Na14Ca6Mn3Zr3[Si26O72(OH)2]Cl2$4H2O, is a new mineral from a khibinite from the northern edge («Anel Norte») of the alkaline Poços de Caldas massif, Minas Gerais, Brazil. The new mineral species has been approved by the CNMNC (IMA 2009-039). Key words: manganoeudialyte, new mineral, eudialyte-group minerals, crystal structure, Poços de Caldas, Minas Gerais, Brazil.

Íîâûé ìèíåðàë ìàíãàíîýâäèàëèò Na14Ca6Mn3Zr3[Si26O72(OH)2]Cl2$4H2O îáíàðóæåí â ñîñòàâå õèáèíèòà èç ñåâåðíîé ÷àñòè ùåëî÷íîãî ìàññèâà Ïîñîñ äå Êàëüäàñ (Ìèíàñ Æåðàèñ, Áðàçèëèÿ) â

35 âèäå àãðåãàòîâ (ðàçìåðîì äî 1 ñì) ðîçîâûõ äî ïóðïóðíûõ çåðåí â èíòåðñòèöèÿõ ìåæäó èíäèâèäàìè ãëàâíûõ ìèíåðàëîâ ïîðîäû, â àññîöèàöèè ñ ýâäèàëèòîì, êàëèåâûì ïîëåâûì øïàòîì, íåôåëèíîì, ýãèðèíîì, àíàëüöèìîì, ñîäàëèòîì, ðèíêèòîì, ëàìïðîôèëëèòîì, àñòðîôèëëèòîì, òèòàíèòîì, ôëþî- ðèòîì è êàíêðèíèòîì. Íîâûé ìèíåðàë ïðîçðà÷íûé äî ïðîñâå÷èâàþùåãî, â ÓÔ ëó÷àõ íå ëþìèíåñ- öèðóåò; õðóïêèé, òâåðäîñòü ïî øêàëå Ìîîñà îò 5 äî 6. Èçìåðåííàÿ ïëîòíîñòü — 2.890 ã/ñì3, âû÷èñ- 3 ëåííàÿ — 2.935 ã/ñì . Ìàíãàíîýâäèàëèò îïòè÷åñêè îäíîîñíûé (+), no = 1.603(2), ne = 1.608(2) (äëÿ áåëîãî ñâåòà). Ïëåîõðîèçì íå ïðîÿâëÿåòñÿ. Õèìè÷åñêèé ñîñòàâ (ìèêðîçîíä, âîäà îïðåäåëåíà ìåòî- äîì Ïåíôèëäà, ìàñ. %): Na2O 12.01, K2O 0.59, CaO 10.70, MnO 3.51, SrO 3.00, FeO 2.72, Al2O3 0.41, La2O3 0.15, Ce2O3 0.12, SiO2 48.70, TiO20.47, ZrO2 12.08, Nb2O5 1.21, HfO2 0.25, F 0.08, Cl 0.99, H2O 3.5, -Oß(Cl,F) –0.26; ñóììà 100.23. Ýìïèðè÷åñêàÿ ôîðìóëà, ðàññ÷èòàííàÿ íà Si + Al + Zr + Ti + + Hf + Nb = 29: H12.08Na12.05Sr0.90K0.39La0.03Ce0.02Ca5.93 (Mn1.54Fe1.18)Zr3.03Nb0.28Al0.25Hf0.04Ti0.18$ Si25.20O79.40Cl0.87F0.13. Êðèñòàëëè÷åñêàÿ ñòðóêòóðà èçó÷åíà ìîíîêðèñòàëüíûì ìåòîäîì (R = 0.033). Ìèíåðàë òðèãîíàëüíûé, ïð. ãð. R3m; a = 14.2418(1), c = 30.1143(3) Å, V = 5289.7(1) Å3, Z = 3. Ìàð- ãàíåö çàñåëÿåò èñêàæåííûé îêòàýäð [MnO4(H2O)2]. Êðèñòàëëîõèìè÷åñêàÿ ôîðìóëà ìàíãàíî- VI V V IV VI ýâäèàëèò: [Na11.93Sr0.81(H3O)0.70K0.39Ce0.07]Ó13.90[Ca6][ Mn1.56 Fe1.20 Na0.24]Ó3.00[Zr3][ (Si0.38Al0.25) IV VI (Nb0.29Zr0.08)]Ó1.00[ Si0.81 Ti0.19]Ó1.00[Si24O72][(OH)2]$[(H2O)3.55Cl0.88(OH)0.84O0.40F0.13]Ó5.80. Ñèëüíûå ëèíèè ïîðîøêîâîé ðåíòãåíîãðàììû [d, Å (I,%)(hkl)]: 6.421 (37) (104), 4.329 (30) (205), 3.526 (46) (027), 3.218 (100), 3.023 (25) (042), 1.609 (77) (4.1.15), 1.605 (41) (4.0.16). ÈÊ-ñïåêòð ñîäåðæèò ïîëî- –1 2+O –1 ñû ìîëåêóë âîäû äâóõ òèïîâ (ïðè 1620 è 1677 ñì ) è ïîëèýäðîâ (Fe 5) (ïðò 529 ñì ). Ìèíåðàë óòâåðæäåí ÊÍÌÍÌ ÌÌÀ (IMA No. 2009-039). Êëþ÷åâûå ñëîâà: ìàíãàíîýâäèàëèò, íîâûé ìèíåðàë, ìèíåðàëû ãðóïïû ýâäèàëèòà, êðèñòàëëè÷å- ñêàÿ ñòðóêòóðà, Ïîñîñ äå Êàëüäàñ, Ìèíàñ Æåðàèñ, Áðàçèëèÿ.

INTRODUCTION

Manganoeudialyte, ideally Na14Ca6Mn3Zr3[Si26O72(OH)2]Cl2·4H2O, has been approved by the CNMNC (IMA 2009-039). The mineral is the Mn-analogue of eudialyte and is named following the nomenclature of eudialyte-group minerals (Johnsen et al., 2003). It may be classified in the Strunz and Nickel (2001) class 9.CO. Type material is deposited in the Mu- seu de Geociências, Instituto de Geociências, Universidade de São Paulo, São Paulo, SP, Brazil (http://www2.igc.usp.br/museu/), specimen number DR704. Eudialyte-group minerals are Na-rich zirconosilicateswith varying amounts of the speci- 2+ 2+ 3+ 2+ 3+ 2+ + 4+ 5+ 6+ + es-determining cations Ca ,Fe ,Fe ,Mn , REE ,Sr ,K ,Ti ,Nb ,W and H3O ,wa- – – – 2– 2– ter molecules, and additional anions Cl ,F,OH, CO3 , SO4 . Their general formula (John- $ sen et al., 2003) can be written as N(1)3N(2)3N(3)3N(4)3N(5)3M(1)6M(2)3—6M(3)M(4) d Å d Å d Å Z3[Si24O72]O’4—6X2. They are trigonal, a 14 , c 30 (rarely 60 ), crystallizing in R3m, R3m or R3. Eudialyte-group minerals belong to the large family of alkaline silicates with heteropolyhedral frameworks. A framework consisting of SiO4 tetrahedra and MO6 oc- tahedra (where M is usually Ti, Nb, or Zr) is a specific structure feature of these minerals (Chukanov and Pekov, 2005). Lately, the number of minerals in this group has increased rapidly and is now 25 (inclu- ding manganoeudialyte). Most of them are reported in Rastsvetaeva (2007). Eudialyte s.l. was reported in the rocks of the Poços de Caldas alkaline massif, Minas Gerais, Brazil, by Guimarães (1948) and Ulbrich and Ulbrich (1992). Microprobe analyses were obtained by Gualda and Vlach (1996) and Johnsen and Gault (1997). On the basis of optical data, Gualda and Vlach (1996) classified one specimen as «eudialyte» (uniaxial positive), another one as «mesodialyte» (optically isotropic), and two specimens as «eucolite» (uniaxial negative). Johnsen et al. (1997) showed that the terms «mesodialyte» and «eucolite» are meaningless. Following the sequence of steps defined by Johnsen and Grice (1999), the eudialyte group minerals from Poços de Caldas are classified as eudialyte (sensu stricto) [either the «eudialyte» or the «mesodialyte» of Gualda and Vlach (1996), and the Poços de Caldas specimen studied by Johnsen and Gault (1997)], kentbrooksite [one «eucolite» studied by Gualda and Vlach (1996)], and ferrokentbrooksite [the other «eucolite» of Gualda and Vlach (1996)] (Atencio et al., 2000).

36 OCCURRENCE

The new eudialyte-group mineral manganoeudialyte occurs in a khibinite, at the northern edge («Anel Norte») of the Upper Cretaceous alkaline Pocos de Caldas massif, a circu- lar intrusion of almost 800 km2, Minas Gerais, Brazil. Emplaced in Precambrian basement rocks and Jurassic sandstones, the intrusion consists of tinguaite, phonolite, nepheline syenite, phonolitic lavas, volcanoclastics, lujavrite and khibinite. Hydrothermal alteration and ore deposition have occurred in all rock types, with emphasis on the inner tinguaite and nepheline syenite. Two small lujavrite-khibinite bodies, an eastern and a western one, are exposed at the northern edge of the alkaline Poços de Caldas massif, southeastern Brazil. Detailed mapping reveals at the center of the better exposed western body a coarse-grained, mesocratic, gneis- sic-looking eudialyte-nepheline syenite (lujavrite) with a strong subhorizontal foliation, showing at the contacts a finer-grained border facies. Two trachytoid nepheline syenite types occur as an envelope to the central lujavrites, followed by an outer shell of coarse-grained eudialyte-nepheline syenite. The internal structure of both bodies is that of a saucer, with successive foliated shells (in part absent in the eastern body), with rather steep dips at the contacts between the different fades; all are surrounded by the outer nepheline syenite. Co- untry rocks are tinguaites and a grey nepheline syenite. Tinguaites were the earliest rocks (intruded some 76—80 Ma ago), followed by the coarser rocks. The emplacement of the lujavrite bodies was a continuous process, initiated with forceful subhorizontal intrusion of strongly agpaitic magmas. Magma upwelling compressed the initial magma batch, genera- ting the lujavrite caps by compaction and liquid extraction, with a foliated subhorizontal structure and an outer shell. The intrusion forced at the same time a lateral expansion of the magma chamber. In this massif, agpaitic magmas appear always as late intrusions. A compa- rison with other occurrences (Ilimaussaq, Lovozero, Pilansberg, the Texan Trans-Pecos pro- vince) suggests that emplacement under forceful conditions may be a controlling factor in shaping the final fabric of lujavrites (Ulbrich, Ulbrich, 2000). The mineral association of manganoeudialyte includes eudialyte, K-feldspar, nepheline, aegirine, analcime, sodalite, rinkite, lamprophyllite, astrophyllite, titanite, fluorite, and can- crinite.

HABIT AND PHYSICAL PROPERTIES

Manganoeudialyte is concentrated in cm-sized patches interstitial to the main minerals of the rock. Khibinite from Poços de Caldas contains both eudialyte and manganoeudialyte. We could distinguish them uniquely by chemical analysis. We identified only eudialyte in some samples, crystals with both species in other samples, and solely manganoeudialyte in other rock fragments. Colour is pink to purple, streak is white, and luster is vitreous. The mineral is transparent (as individual crystals) to translucent (massive). It is not fluorescent under both long- and short-wave ultraviolet light. Mohs hardness is between 5 and 6, tenacity is brittle. Neither cleavage nor parting were observed; fracture is uneven. Measured density is 2.890 g/cm3 by sink/float in bromoform-methylene iodide mixtures; the calculated density is 2.935 g/cm3 based on the empirical formula and unit cell parameters from the single-crystal study. In transmitted light, manganoeudialyte is uniaxial (+) and has w = 1.603(2), e = = 1.608(2) (white light). It is nonpleochroic. Wavenumbers of absorption bands in the IR spectrum (Fig. 1) of manganoeudialyte and their assignments are (cm–1; s — strong band, w — weak band, sh — shoulder): 3440 (O—H stretching vibrations of H-bonded groups), 1677w, 1620w (HOH bending vibrations of H2O molecules), 1135sh, 1052sh, 1017s, 978s (Si—O stretching vibrations of tetrahedral rings), 933s (Si—O stretching vibrations of M3 and M4 tetrahedra), 740, 696, 661, 580w (mixed Si-O stretching and OSiO bending vibrations), 529 (stretching vibrations of FeO5 polyhedra), 477s, 450s, 415sh (SiOSi bending vibrations combined with different stretching vibrations cation—oxygen).

37 Fig. 1. IR spectrum of manganoeudialyte. Ðèñ. 1. ÈÊ-ñïåêòð ìàíãàíîýâäèàëèòà.

From the IR spectrum of manganoeudialyte (Fig. 1), it follows that the mineral contains locally different water molecules corresponding to non-degenerate HOH bending modes (bands at 1620 and 1677 cm–1). Bands for [IV]Fe2+-O vibrations (at 542—545 cm–1) are absent in the IR spectrum. Instead, a band at 529 cm–1 is observed, corresponding to [V]Fe2+—O stretching vibrations.

CHEMICAL DATA

Chemical analyses (12) were carried out by means of an electron microprobe (WDS mode, 15 kV, 20 nA, 20 mm beam diameter, count time = 10—50 s on peak and background). H2O content determined by the modified Penfield method (selective sorption of H2Oon Mg(ClO4)2 from gaseous products obtained by heating of the mineral in oxygen at 1060 °C) 2– is 3.5(3) wt%. CO3 groups are absent (from IR data). Analytical data are given in Table 1. $ The empirical formula, based on Si + Al + Zr + Ti + Hf + Nb = 29 is: H12.08Na12.05Sr0.90 K0.39La0.03Ce0.02Ca5.93(Mn1.54Fe1.18)Zr3.03Nb0.28Al0.25Hf0.04Ti0.18Si25.20O79.40Cl0.87F0.13. The crystal chemical formula, derived from and consistent with the results of the single-crystal X-ray VI V V $ structure analysis is [Na11.93Sr0.81(H3O)0.70K0.39Ce0.07](13.90[Ca6][ Mn1.56 Fe1.20 Na0.24]S3.00 IV VI IV VI $ [Zr3][ (Si0.38Al0.25) (Nb0.29Zr0.08)]S1.00 [ Si0.81 Ti0.19]S1.00 [Si24O72] [(OH)2][(H2O)3.55Cl0.88 $ (OH)0.84O0.40F0.13]S5.80. The simplified, end-member formula is Na14Ca6Mn3Zr3 [Si26O72(OH)2]Cl2.4H2O, which requires Na2O 14.18, CaO 11.00, MnO 6.96, SiO2 51.05, ZrO2 12.08, Cl 2.32, H2O 2.94, -O=Cl –0.52, total 100.00. The maximum content of Na can be 14 but not 15 apfu: the N5 site is occupied only partly by Na ions because this site is situa- ted near OH groups (the distance between them is less than 2 Å) due to the orientation of SiO3(OH) tetrahedra into the hole between the nine-membered rings.

CRYSTALLOGRAPHY

Powder X-ray diffraction data were obtained using a Siemens D5000 diffractometer equ- ipped with a Göbel mirror and a position-sensitive detector. X-ray powder-diffraction data Å (in for CuKa) are given in Table 2. Unit cell parameters refined from powder data are: Tri- gonal, Space Group: R3m, a = 14.253(1) Å, c = 30.079(4) Å, V = 5292(1) Å3, Z = 3. Sing- le-crystal X-ray studies were carried out using an Xcalibur S diffractometer (Oxford Diffrac- Å tion Ltd) with a CCD detector (MoKa = 0.7107 ), and gave the following data: Trigonal, Space group: R3m, a = 14.2418(1), c = 30.1143(3) Å, V = 5289.7(1) Å3, Z = 3. The c:a ratio calculated from the unit-cell parameters is 2.115. The crystal-structure data and characteristics of the XRD study are given in Table 3. Calculations using the Gladstone-Dale relationship for the empirical formula and the cell data derived from the single-crystal studies yield

38 Table 1 Chemical data for manganoeudialyte Õèìè÷åñêèé ñîñòàâ ìàíãàíîýâäèàëèòà

Constituent wt % Range SD Probe standard

Na2O 12.01 11.39—12.43 0.30 Amelia albite K2O 0.59 0.57—0.64 0.03 Orthoclase CaO 10.70 9.73—11.06 0.17 Anorthite MnO 3.51 3.04—3.88 0.19 Olivine SrO 3.00 2.68—3.64 0.50 Sr-rich anorthite

Al2O3 0.41 0.07—2.79 0.02 Anorthite FeO 2.72 2.45—2.92 0.12 Olivine

La2O3 0.15 0.03—0.26 0.10 REE3 Ce2O3 0.12 0.03—0.19 0.10 REE3 Nd2O3 0.00 0.00—0.03 0.05 REE2 SiO2 48.70 48.24—49.14 0.27 Wollastonite TiO2 0.47 0.33—0.59 0.06 Rutile ZrO2 12.08 11.24—12.50 0.44 Zr Nb2O5 1.21 0.93—1.72 0.08 Nb HfO2 0.25 0.15—0.35 0.10 Hafnia F 0.08 0.00—0.23 0.30 Fluorapatite Cl 0.99 0.91—1.06 0.10 Chlorapatite

H2O 3.5 –O=(Cl,F) –0.26 Total 100.23

Table 2 Powder X-ray diffraction data for manganoeudialyte Ïîðîøêîâûå ðåíòãåíîãðàôè÷åñêèå äàííûå äëÿ ìàíãàíîýâäèàëèòà

I (%) dmeas. Å dcalc. Å hk lI(%) dmeas. Å dcalc. Å hkl

10 11.537 11.414 1 0 1 5 2.137 2.137 3 1 11 11 7.155 7.121 1 1 0 11 2.125 2.125 5 1 4 37 6.421 6.426 1 0 4 1 2.114 2.119 0 1 14 11 6.022 6.042 0 2 1 2 2.098 2.097 1 4 9 8 5.726 5.707 2 0 2 5 2.062 2.063 5 0 8 4 5.394 5.412 0 1 5 4 2.059 2.062 3 2 10 3 4.619 4.607 2 1 1 1 2.051 2.051 2 2 12 1 4.463 4.453 1 2 2 1 2.049 2.049 2 4 7 30 4.329 4.309 2 0 5 2 2.046 2.047 0 4 11 10 4.103 4.102 1 1 6 1 2.027 2.031 2 0 14 3 3.966 3.963 2 1 4 1 2.025 2.023 4 3 1 5 3.805 3.805 3 0 3 1 2.015 2.014 0 6 3 3 3.687 3.686 1 2 5 1 1.983 1.982 4 2 8 46 3.526 3.528 0 2 7 1 1.976 1.975 5 2 0 8 3.404 3.399 1 3 1 1 1.966 1.968 2 3 11 100 3.218 3.213 2 0 8 1 1.959 1.958 4 3 4 13 3.160 3.162 2 1 7 1 1.940 1.938 2 5 3 25 3.023 3.021 0 4 2 1 1.923 1.922 3 4 5 9 2.974 2.974 3 1 5 1 1.910 1.909 1 5 8

39 Table 2(continuation)

I (%) dmeas. Å dcalc. Å hk lI(%) dmeas. Å dcalc. Å hkl

2 2.927 2.929 1 2 8 2 1.904 1.902 6 0 6 2 2.921 2.925 1 0 10 1 1.868 1.866 6 1 2 15 2.854 2.853 4 0 4 1 1.843 1.843 2 4 10 3 2.693 2.691 4 1 0 4 1.836 1.835 4 1 12 2 2.667 2.673 0 1 11 <1 1.827 1.825 1 6 4 9 2.647 2.649 3 2 4 3 1.802 1.804 0 3 15 4 2.596 2.595 0 3 9 3 1.802 1.800 0 2 16 3 2.534 2.532 3 1 8 2 1.798 1.795 6 1 5 1 2.528 2.530 2 1 10 <1 1.791 1.792 3 2 13 1 2.508 2.510 0 0 12 2 1.782 1.780 4 4 0 1 2.505 2.505 4 0 7 1 1.774 1.775 4 2 11 1 2.460 2.459 0 5 1 16 1.763 1.764 0 4 14 2 2.437 2.438 2 2 9 7 1.758 1.759 3 5 1 <1 2.385 2.385 0 4 8 1 1.751 1.752 6 0 9 1 2.378 2.374 3 3 0 1 1.751 1.750 5 3 2 1 2.374 2.372 1 4 6 1 1.751 1.749 2 2 15 <1 2.346 2.344 0 5 4 1 1.742 1.745 2 1 16 1 2.327 2.324 2 4 1 1 1.724 1.724 3 3 12 2 2.311 2.310 3 3 3 1 1.722 1.722 1 5 11 1 2.303 2.303 4 2 2 1 1.716 1.716 7 0 4 1 2.273 2.277 1 0 13 1 1.701 1.703 2 0 17 1 2.261 2.262 2 3 8 <1 1.693 1.691 0 7 5 1 2.261 2.260 1 3 10 2 1.678 1.678 4 4 6 1 2.229 2.227 2 4 4 1 1.669 1.668 6 2 4 1 2.210 2.209 5 1 1 2 1.646 1.645 2 6 5 1 2.193 2.192 1 5 2 2 1.646 1.645 4 4 7 4 2.175 2.174 4 2 5 1 1.643 1.643 2 4 13 1 2.147 2.146 3 3 6 1 1.626 1.629 1 1 18 7 2.141 2.142 3 0 12 2 1.621 1.621 5 0 14 7 2.141 2.140 0 5 7 3 1.615 1.612 1 7 3 77 1.609 1.609 4 1 15 1 1.547 1.546 5 4 4 41 1.605 1.607 4 0 16 18 1.542 1.543 1 5 14 2 1.601 1.601 5 1 13 18 1.542 1.540 0 8 1 <1 1.595 1.596 0 7 8 1 1.536 1.536 3 6 3 <1 1.595 1.595 1 6 10 1 1.536 1.535 0 2 19 1 1.590 1.590 6 0 12 <1 1.534 1.534 8 0 2 1 1.590 1.589 6 2 7 <1 1.534 1.533 3 3 15 <1 1.580 1.581 4 2 14 4 1.524 1.526 4 3 13 4 1.571 1.571 4 5 2 1 1.621 1.521 7 0 10 <1 1.565 1.567 3 2 16 <1 1.512 1.514 2 2 18 <1 1.555 1.554 6 3 0 <1 1.512 1.510 0 8 4 <1 1.552 1.552 5 2 12 1 1.486 1.487 6 2 10 1 1.550 1.550 6 1 11 2 1.482 1.482 0 7 11 1 1.550 1.550 3 0 18 2 1.478 1.478 2 7 4

Kp (constant derived from physical properties) = 0.2061 and Kc (constant derived from chemical analysis) = 0.2103. Hence1–(Kp /Kc) is 0.020 indicating excellent compatibility (Mandarino, 1979). Crystal structure has been refined using AREN-program (Andrianov, 1987) to R = 0.033 s for 3129 independent reflections with F>3 (F); Rint = 0.007; total reflections = 100940, in- dex limits — 27 > h 26; –28 > k < 31; –66 > l<63. Manganoeudialyte is an analogue of eudialyte with Mn prevailing over other components in the group of sites M2 whose composition

40 Table 3 Crystal data, data collection and refinement details for the structure Êðèñòàëëîãðàôè÷åñêèå õàðàêòåðèñòèêè, äàííûå ìîíîêðèñòàëüíîé ðåíòãåíîãðàôèè è óòî÷íåíèÿ ñòðóêòóðû

Crystal data Formula [Na11.93Sr0.81(H3O)0.70K0.39Ce0.07]S13.90$ VI V V IV VI [Ca6][ Mn1.56 Fe1.20 Na0.24]S3.00[Zr3][ (Si0.38Al0.25) (Nb0.29Zr0.08)]S1.00$ IV VI [ Si0.81 Ti0.19]S1.00[Si24O72][(OH)2][(H2O)3.55Cl0.88(OH)0.84O0.40F0.13]S5.80 Space group R3m a, ñ (Å) 14.2418(1), 30.1143(3) V (Å3), Z 5289.7(1), 3 F(000) 4576.65 m (mm–1) 27.22 Crystal dimensions (mm) 0.1%0.15%0.25

Data collection Diffractometer Xcalibur S diffractometer (Oxford Diffraction Ltd) with a CCD detector Temperature (K) 293 Radiation Moka, l = 0.7107 Å q range (°) 3.7484 to 54.3427 Detector distance (mm) 50 Rotation axis w Total number of frames 2653 Collection time per frame (s) 8 to 30 h, k, l ranges –27 D 26, –28 D 31, –66 D 63 Total reflections measured 100940 Unique feflections 3129 (Rint = 0.7 %) Refinement Refinement on F2 R1* for Fo >4s(Fo) 0.033 Number of parameters refined 477 Extinction coefficient 0.0000001 max 3 Drmin, Dr (e/Å ) –1.5, 0.82

*R1=S||Fo|–|Fc|| / S|Fo|

is Mn1.56Fe1.20Na0.24 (for Z = 3). Polyhedral representation of the whole structure and its fragments are given in Figures 2 and 3. Mn cations have octahedral coordination with H2O molecules at two vertices of each Mn octahedron. As a result, manganoeudialyte contains more water pfu than eudialyte. The oxygen atoms have been assigned to OH and H2O on the basis of local valency balance. Atom coordinates, occupancies and equivalent isotropic displacement parameters are given in Table 4. As in eudialyte, in manganoeudialyte Si prevails over Nb in both sites near the centers of 9-membered tetrahedral rings (the sites M3a, M4b and M4c). The main distinc- tion of manganoeudialyte from another non-centrosymmetric Mn-dominant mineral kent- $ brooksite (Na,REE)15(Ca,REE)6Mn3Zr3NbSi25O74F2 2H2O (Johnsen et al., 1998) is the predominance of Si over other components in M3 and M4 sites. Note that eudialyte-group minerals with high Si contents should not be considered a priori as being centrosymmetric (Johnsen, Grice, 1999). Even for eudialyte with the maximum content of 26 Si atoms (Z = = 3) it is far from certain that they are centrosymmetric because, for this to be the case, corresponding orientation of additional SiO4 tetrahedra (at the centers of the 9-membered rings) is required. Ordering of other components also plays an important role in the symmetry of eudialyte-group minerals.

41 Fig. 2. Polyhedral representation of the whole structure along the threefold axis. Fe- and Na-centered pyramids are omitted. Ðèñ. 2. Ïîëèýäðè÷åñêîå ïðåäñòàâëåíèå ïîëíîé ñòðóêòóðû âäîëü òðîéíîé îñè. Fe- è Na-öåíòðèðîâàííûå ïèðàìèäû îïóùåíû.

Fig. 3. Predominant situation around the M2 site (W =H2O).

Ðèñ. 3. Äîìèíèðóþùàÿ ñèòóàöèÿ â îêðåñòíîñòè ïîçèöèè M2(W =H2O). 42 Table 4 Atom coordinates, multiplicities (Q), occupancies (q) and equivalent isotropic displacement parameters for manganoeudialyte Êîîðäèíàòû àòîìîâ, êðàòíîñòè (Q), çàñåëåííîñòè (q) è ïàðàìåòðû àòîìíûõ ñìåùåíèé äëÿ ìàíãàíîýâäèàëèòà

2 Site x/ay/bz/cQ qBeq, Å

Zr 0.3325(1) 0.1663(1) 0.1668(1) 9 1 1.05(2) M1 –0.0001(1) 0.2601(1) 0 18 1 0.65(3) Si1 0.5260(1) 0.2630(1) 0.2514(1) 9 1 0.47(9) Si2 –0.0056(1) 0.6036(1) 0.0976(1) 18 1 0.59(6) Si3 0.2081(1) 0.4162(1) 0.0770(1) 9 1 0.83(8) Si4 0.0827(2) 0.5413(1) 0.2585(1) 9 1 1.07(8) Si5 0.0570(1) 0.3267(1) 0.2369(1) 18 1 0.78(6) Si6 0.1404(1) 0.0702(1) 0.0826(1) 9 1 0.77(8) O1 0.4790(5) 0.2395(3) 0.2006(1) 9 1 1.4(3) O2 0.2600(3) 0.0334(3) 0.2085(1) 18 1 1.3(2) O3 0.4061(5) 0.3047(4) 0.1275(1) 18 1 2.2(2) O4 0.6052(2) 0.3948(2) 0.2562(2) 9 1 1.3(3) O5 0.4352(4) 0.2171(3) 0.2884(1) 9 1 0.8(3) O6 0.4114(3) 0.0338(4) 0.0453(1) 18 1 1.5(2) O7 0.1011(3) 0.3795(4) 0.1076(1) 18 1 1.4(2) O8 0.0207(5) 0.5103(3) 0.1150(1) 9 1 1.0(3) O9 0.2740(3) 0.5480(4) 0.0685(5) 9 1 4.5(3) O10 0.1809(2) 0.3619(2) 0.0287(1) 9 1 0.8(3) O11 0.0282(6) 0.5141(4) 0.3052(2) 9 1 1.5(3) O12 0.1765(3) 0.3539(5) 0.2184(2) 9 1 1.7(3) O13 0.0443(2) 0.3001(3) 0.2885(1) 18 1 0.7(1) O14 0.3871(4) 0.4321(4) 0.2271(1) 18 1 2.2(2) O15 0.3952(3) 0.6048(3) 0.2526(3) 9 1 2.2(3) O16 0.0618(2) 0.1237(3) 0.0782(2) 9 1 1.2(3) O17 0.1891(5) 0.0946(4) 0.1312(1) 9 1 1.6(3) O18 0.2260(5) 0.1130(4) 0.0433(2) 9 1 1.4(3) M2a 0.4928(1) 0.5070(1) 0.0017(1) 9 0.52(2) 1.00(3) M2b 0.5200(1) 0.4800(1) –0.0023(1) 9 0.40(3) 0.67(4) M2c 0.134(1) 0.268(2) 0.3340(8) 9 0.08(1) 0.7(3) M3a 0.3333 0.6667 0.2454(3) 3 0.38(3) 1.1(1) M3b 0.3333 0.6667 0.2839(9) 3 0.25(3) 3.4(2) M3c 0.3333 0.6667 0.2966(1) 3 0.37(3) 0.94(4) M4a 0.3333 0.6667 0.0429(3) 3 0.19(4) 1.5(2) M4b 0.3333 0.6667 0.0518(3) 3 0.37(3) 2.7(1) M4c 0.3333 0.6667 0.0900(2) 3 0.44(3) 0.4(2) N1a 0.1128(2) 0.2256(4) 0.1523(1) 9 0.79(1) 2.3(1) N1b 0.0925(9) 0.185(1) 0.1620(7) 9 0.21(3) 2.4(2) N2a 0.5839(7) 0.4163(7) 0.1638(4) 9 0.40(2) 3.5(2) N2b 0.5585(3) 0.4415(3) 0.1785(2) 9 0.60(2) 1.9(1) N3a 0.2358(2) 0.4716(3) –0.0443(2) 9 0.36(3) 1.0(1) N3b 0.2220(5) 0.1106(4) 0.2837(2) 9 0.64(2) 1.9(1) N4a 0.4292(7) 0.2150(5) 0.0569(3) 9 0.36(3) 1.2(2) N4b 0.4653(1) 0.2327(1) 0.0494(1) 9 0.29(3) 0.95(6) N4c 0.485(1) 0.2426(8) 0.0450(3) 9 0.35(3) 2.0(0) N5a 0.2512(7) 0.502(1) 0.1733(5) 9 0.23(4) 4.7(4) N5b 0.1897(7) 0.5949(5) 0.1460(3) 9 0.40(3) 2.8(2)

43 Table 4(continuation)

2 Site x/ay/bz/cQ qBeq, Å

C11 0.6667 0.3333 0.1008 (3) 3 0.48(3) 2.1(2) Ñ12 0 0 0.2401(3) 3 0.40(1) 4.7(2) F 0.6667 0.3333 0.036(3) 3 0.13(4) 1.82(0) OH1 0.3333 0.6667 0.1426(6) 3 0.44(2) 1.1(8) OH2 0.3333 0.6667 0.196(2) 3 0.38(3) 3.6(6) OH3 0.3333 0.6667 –0.0045(4) 3 0.37(3) 9.0(1) OH4 0.3333 0.6667 0.341(2) 3 0.25(3) 3.6(7) W1* 0.240(2) 0.620(1) 0.0009(6) 9 0.60(2) 6.9(2) W2** 0.6020(3) 0.2040(4) –0.0039(2) 9 0.92(1) 2.20(7) W3 0.6667 0.3333 0.123(3) 3 0.36(9) 8.5(6) W4 0 0 0.252(1) 3 0.43(5) 2.6(7) Note: W1—W4 are water-containing sites; *W1 = (H2O)1.2 + (OH)0.6;**W2=(H2O)1.56 + (O,OH)1.2.

Table 5 Site, refined numbers of electrons (Epfu) for cation sites with mixed occupancies, composition, coordination number (CN), and selected bond lengths to O (Å) in manganoeudialyte Ïîçèöèè, óòî÷íåííûå êîëè÷åñòâà ýëåêòðîíîâ (Epfu — äëÿ ñìåøàííîçàñåëåííûõ ïîçèöèé), ñîñòàâû ïîçèöèé, ê. ÷. (CN) è ðàññòîÿíèÿ äî àòîìà O (Å) â ìàíãàíîýâäèàëèòå

Selected bond lengths, Å Conposition Site Epfu CN (Z = 3) minimum maximum mean

Zr 3Zr 6 2.065(4) 2.077(5) 2.071 M1 6Ca 6 2.303(4) 2.399(3) 2.361 M2a 39.1 1.56Mn 6 2.07(1) 2.78(1) 2.30 M2b 31.1 1.2Fe 5 2.024(4) 2.171(3) 2.104 M2c 2.9 0.24Na 5 2.07(2) 2.36(2) 2.20 M3a 5.3 0.38Si 4 1.540(1) 1.540(5) 1.540 M3b 3.3 0.25Al 4 1.72(6) 1.79(1) 1.77 M3c 15.1 0.29Nb+0.08Zr 6 1.876(6) 2.022(6) 1.949 M4a 4.2 0.19Ti 6 1.65(1) 1.71(2) 1.68 M4b 5.2 0.37Si 4 1.55(1) 1.68(4) 1.58 M4c 6.1 0.44Si 4 1.58(2) 1.60(1) 1.60 N1a 26.1 2.37Na 8 2.541(8) 2.687(7) 2.636 N1b 6.9 0.63Na 6 2.48(2) 2.68(2) 2.57 N2a 13.2 1.2Na 8 2.38(5) 2.83(1) 2.57 N2b 19.9 1.8Na 9 2.56(1) 3.14(5) 2.69 N3a 15.8 0.69Na 11 2.48(1) 2.96(1) 2.69 0.39K 9 2.563(6) 2.961(6) 2.736 N3b 21.1 1.92Na 11 2.49(1) 3.05(2) 2.74 N4a 11.9 1.07Na 6 2.47(1) 2.69(1) 2.56 N4b 35.1 0.81Sr+0.07Ce 11 2.51(1) 2.96(1) 2.73 N4c 11.6 1.05Na 11 2.25(1) 3.19(1) 2.60 N5a 5.5 0.7H3O 9 2.14(2) 3.05(1) 2.70 N5b 13.2 1.2Na 7 2.29(1) 2.91(1) 2.66

44 Table 6 Bond lengths (Å) for Fe- and Mn-polyhedra Äëèíû ñâÿçåé (Å) äëÿ Fe- è Mn-ïîëèýäðîâ

Fe—W2(W2=O,OH) 2.024(4) Fe—O6%2 2.078(4) Fe — O13%2 2.171(3) Mean 2.104 Mn — O13%2 2.07(1) Mn—O6%2 2.08(1) Mn — W2 2.70(1) Mn — W1 2.78(1) Mean 2.30

Site compositions, refined numbers of electrons for cation sites with mixed occupancies, coordination numbers and selected bond lengths for the metal-bearing sites are given in Table 5. Bond lengths (Å) for Fe- and Mn-polyhedra are given in Table 6. Mn and Fe differ by only one electron but essentially differ in their ionic radii that allowed us to distribute them in the positions M2a and M2b respectively. The site M2 having 4-fold coordination (flat square, characteristic of eudialyte sensu stricto) is vacant in manganoeudialyte. Instead, there are three subsites in this region (M2a, M2b and M2c) with the distances M2a — M2b, M2a — M2c and M2b — M2c equal to 0.67(1), 0.68(1) and 1.34(1) A respectively and coordination numbers from 5 to 6 (Table 5). The largest octahedron M2a with distances M2a — % % Å O 2.07 2; 2.08 2 and M2a—H2O 2.67 and 2.78 A (mean 2.30 ) contains the largest M2-cation. Thus we conclude that the site M2a is occupied mainly with Mn. The small tetragonal pyramid with distances M2b — O 2.024, 2.075%2; 2.171%2 Å (mean 2.10 Å) is occupied by a smaller cation. Taking into account that effective ionic radii are 0.77 Å for VIFe2+, 0.645 Å for VIFe3+, 0.63 for IVFe2+ and 0.82 Å for VIMn2+ (Shannon, Prewitt, 1969), we can conclude that the site M2a is occupied preferably with Mn2+ (with the occupancy of 0.52) and the site M2b — with Fe2+ (with the occupancy of 0.40). Note that the ratio of occupancies in M2a and M2b (0.52:0.40 = 1.30) is close to the ratio of total Mn to total Fe in the empirical formula of manganoeudialyte (1.54:1.18 = 1.305). The presence of minor amount of Fe in the large Mn-octahedron can not be excluded. In any case we should take into account that species-determining feature is the predominance of a certain cation in the site M2 as a whole (Johnsen et al., 2003), but not in its subsites. The third subsite M2c is established from the electron density map and refined as minor amount of light element like Mg or Na. Taking into account that Mg was not found in manganoeudialyte using electron microprobe analysis, M2c cation was modeled by Na. The at- tempts to place in this position a heavier element (like Fe) were unsuccessful: thermal para- meter was too high. Being modeled by Mg or Na, this site should have the occupancy of 0.08 that means about 1 electron per site. Similar Na pyramid with rather small dimensions (Na—O distances from 2.087 to 2.274 Å, mean 2.173 Å; Table 5) was found earlier in rasla- kite (Ekumenkova et al., 2000). We have calculated a set of normalized structure factors E, and IE2-1I statistics have the value 0.903. This is in the range 0.75—0.96, characteristic of non-centrosymmetric eudialyte (R3m). Thus, in spite of the fact that Si prevails both in M(3) and M(4), manganoeudialyte is acentric.

DISCUSSION

The presence of cations being very different by size and charge characteristics results in complex and unusual mechanisms of isomorphous substitutions that can be realized in minerals with heteropolyhedral frameworks. In particular, in eudialyte-group minerals the following mechanisms are known.

45 2+ 1. Substitutions accompanied by a change of coordination is possible, e.g.: Fe O4 (squa- D 3+ D 3+ re) Fe O5 (tetragonal pyramid) Fe O6 (octahedron). 2. Isomorphous substitutions between cations very different by charge: Na+ D Al3+ D D Si4+ D Nb5+ D W6+ (at the centre of the nine-membered rings); Na+ D Fe2+ D Zr4+ D Ta5+ (in the position with 4-fold planar coordination linking the rings of the CaO6 octa- hedra). 3. The possibility of selective ordering of cations in different framework and extra-framework sites along with the existence of disordered analogues. 4. Substitution of Na for H3O, H and H2O. Strongly hydrated and «decationized» samples of eudialyte-group minerals are common. Manganoeudialyte is an example of eudialyte-group mineral with mixed occupancies of several key domains. Unlike sites sensu stricto, domains can be defined as microregions in the unit cell that can host a number of alternative sites having, in a general case, different coordination numbers. In eudialyte-group minerals, each of the key domains, M2, M3 and M4, can be alternatively occupied by different cations having various coordinates, coordination numbers and charges. Manganoeudialyte is characterized by the predominance 2+ of Mn O6 among M2 polyhedra and the predominance of SiO4 among M3 and M4 polyhedra. Minerals close to manganoeudialyte by chemical composition are known from other localities. Their empirical formulae are: —Na14.73K0.225Sr0.29Ca5.43Mn2.07Fe1.57Zr2.60Ti0.39Nb0.36Al0.09Si25.52O72(O,OH,H2O,F)yCl0.52 for a sample from the mountain Eveslogchorr, Khibiny massif, Kola Peninsula (data by I. V. Pekov, personal communication); —Na12.8 K0.32Sr0.44Ca5.71Mn2.12Fe1.30Zr2.66Ti0.25Nb0.19Si25.7O72(O,OH,H2O,F)yCl0.63(SO4)0.22 for a sample from the mountain Lepkhe-Nelm, Lovozero massif, Kola Peninsula (our data); —Na12.23K0.06Sr0.77Ca4.77REE0.56Mn1.61Fe0.74(Zr2.52Ti0.50)Nb0.28Si25.6O72Cl0.40(SO4)0.25(OH, H2O)x for a sample from the mountain Alluaiv, Lovozero massif, Kola Peninsula (our data). Multiple examples of Mn-rich eudialyte-group minerals from different localities, in particular presumable manganoeudialyte, are given by A. Bulakh and T. Petrov (Table 6 in: Bu- lakh, Petrov, 2004).

ACKNOWLEDGEMENTS

We acknowledge FAPESP (Fundação de Amparo à Pesquisa do Estado de São Paulo) for financial support (Processes 2005/53741-1 and 2009/09125-5); the members of the IMA Commission on New Minerals Nomenclature and Classification for their helpful sug- gestions and comments; Isaac Jamil Sayeg for the EDS preliminary chemical analysis. This work was financially supported by Russian Foundation for Basic Research (grant 09-05-12001-ofi_m).

References

Andrianov V. I. Development of the system of crystallographic programs RENTGEN for the computers NORD, CM-4 and EC / Kristallografiya. 1987. 32. Vol. 228—231 (in Russian). Atencio D., Coutinho J. M. V., Silva J. F. Kentbrooksite, ferrokentbrooksite and eudialyte from Poços de Caldas, Minas Gerais / 4th International Conference Mineralogy and Museums. Melbourne, Australia. 2000. Program and Abstract Volume. P. 23. Bulakh A. G., Petrov T. G. Chemical variability of eudialyte-group minerals and their sorting / Neues Jb. Mineral. Mh. 2004. Vol. 2004/3. P. 127—144. Chukanov N. V., Pekov I. V. Heterosilicates with tetrahedral-octahedral frameworks: Mineralogical and crystal-chemical aspects / Reviews in Mineralogy and Geochemistry. 2005. Vol. 57: Micro- and mesoporous mineral phases (Editors: G. Ferraris and S. Merlino). P. 105—143. Ekimenkova I. A., Rastsvetaeva R. K., Chukanov N. V. Ordering of calcium and iron in mineral of eudialyte group with the symmetry R3 / Doklady Akademii Nauk. 2000. Vol. 374. P. 352—355 (in Russian).

46 Gualda G. A. R., Vlach S. R. F. Eudialitas-eucolitas do maciço alcalino Poços de Caldas, MG-SP: quimis- mo e correlações com comportamento óptico / Congresso Brasileiro de Geologia. 1996. Vol. 39. P. 34—37. Guimarães D. The zirconium ore deposits of the Pocos de Caldas plateau, Brazil, and zirconium geochemistry. Boletim: Instituto de Tecnologia Industrial, 1948. Vol. 6. 79 p. Johnsen O., Gault R. A. Chemical variation in eudialyte / N. Jahrb. für Mineral., Abh. 1997. Vol. 171. P. 215—237. Johnsen O., Grice J. D. The crystal chemistry of the eudialyte group / Canadian Mineralogist. 1999. Vol. 37. P. 865—891. Johnsen O., Petersen O. V., Gault R. A. Optical data on minerals of the eudialyte group: Discussion of the eucolite-mesodialyte-eudialyte terminology / N. Jahrb. für Mineral., Mh. 1997. P. 371—383. Johnsen O., Grice J. D., Gault R. A. Kentbrooksite from the Kangerdlugssuaq intrusion, East Greenland, a new Mn-REE-Nb-F end-member in a series within the eudialyte group: Description and crystal structure / Eur. J. Mineral. 1998. Vol. 10. P. 207—219. Johnsen O., Ferraris G., Gault R. A., Grice J. D., Kampf A. R., Pekov I. V. Nomenclature of eudialyte- group minerals. Can. Mineral. 2003. Vol. 41. P. 785—794. Mandarino J. A. The Gladstone-Dale relationship — Part III: Some general applications / Can. Mineral. 1979. Vol. 17. P. 71—76. Rastsvetaeva R. K. Structural mineralogy of the eudialyte group: a review / Crystallography Reports. 2007. Vol. 52. P. 47—64. Shannon R. D., Prewitt C. T. Effective ionic radii in oxides and fluorides / Acta Crystallographica. 1969. Vol. B25. P. 925—946. Strunz H., Nickel E. H. Strunz Mineralogical Tables, 9th edition. Stuttgart: E. Schweizerbart’sche Ver- lagsbuchhandlung (Nägele und Obermiller), 2001. Ulbrich H. H. G. J., Ulbrich M. N. C. O Maciço Alcalino de Poços de Caldas, MG-SP: características pet- rograficas* e estruturais. Roteiros das Excursões do 37° / Congresso Brasileiro de Geologia, São Paulo. 1992. Vol. 5. P. 64. Ulbrich H. H. G. J., Ulbrich M. N. C. The lujavrite and khibinite bodies in the Poços de Caldas alkaline massif, southeastern Brazil: a structural and petrographic study / Revista Brasileira de Geociências. 2000. Vol. 30. P. 615—622. Ïîñòóïèëà â ðåäàêöèþ 26 ôåâðàëÿ 2010 ã.

ÓÄÊ 549.6 + 548.736.64 (470.21) ÇÐÌÎ, ¹ 4, 2010 ã. Zapiski RMO, N 4, 2010

ÔÈÂÅÃÈÒ K4Ca2[AlSi7O17(O2–xOHx)][(H2O)2–xOHx]Cl — ÍÎÂÛÉ ÌÈÍÅÐÀË ÈÇ ÕÈÁÈÍÑÊÎÃÎ ÙÅËÎ×ÍÎÃÎ ÌÀÑÑÈÂÀ (ÊÎËÜÑÊÈÉ ÏÎËÓÎÑÒÐÎÂ, ÐÎÑÑÈß)1

* Ìîñêîâñêèé óíèâåðñèòåò, ãåîëîãè÷åñêèé ôàêóëüòåò, 119899, Ìîñêâà, Âîðîáüåâû ãîðû; e-mail: [email protected] ** Èíñòèòóò ïðîáëåì õèìè÷åñêîé ôèçèêè ÐÀÍ, 142432, ã. ×åðíîãîëîâêà, Ìîñêîâñêàÿ îáë. *** ÍÏÏ «Òåïëîõèì», 127238, Ìîñêâà, Äìèòðîâñêîå øîññå, 71

Íîâûé ìèíåðàë ôèâåãèò K4Ca2[AlSi7O17(O2–xOHx)][(H2O)2–xOHx]Cl (x = 0—2) óñòàíîâëåí íà ãîðå Ðàñâóì÷îðð â Õèáèíñêîì ùåëî÷íîì ìàññèâå (Êîëüñêèé ïîëóîñòðîâ, Ðîññèÿ), â óëüòðààãïàè- òîâîì ïåãìàòèòå. Îáñóæäàåòñÿ ñåðèÿ ïîñëåäîâàòåëüíûõ òðàíñôîðìàöèé: äåëüõàéåëèò K4Na2Ca2$ [AlSi7O19]F2Cl D ôèâåãèò D ãèäðîäåëüõàéåëèò KCa2[AlSi7O17(OH)2](H2O)6–x. Êëþ÷åâûå ñëîâà: ôèâåãèò, íîâûé ìèíåðàë, äåëüõàéåëèò, ãèäðîäåëüõàéåëèò, ñëîèñòûå ñèëèêàòû, êðèñòàëëè÷åñêàÿ ñòðóêòóðà, âûñîêîùåëî÷íûå ïåãìàòèòû, Õèáèíñêèé ùåëî÷íîé ìàññèâ, Êîëüñêèé ïîëóîñòðîâ.

1 Íîâûé ìèíåðàë ôèâåãèò è åãî íàçâàíèå îäîáðåíû Êîìèññèåé ïî íîâûì ìèíåðàëàì ÐÌÎ è óòâåðæäåíû Êîìèññèåé ïî íîâûì ìèíåðàëàì, íîìåíêëàòóðå è êëàññèôèêàöèè ìèíåðàëîâ ÌÌÀ 5 íîÿáðÿ 2009 ã., IMA No 2009-067.