Canadian Mineralogist Vol. 18, pp. 201-203 (1980)

GITTINSITE,A NEW CALCIUM ZIRCONIUM SILICATE FROM THE KIPAWAAGPAITIC SYENITE COMPLEX, OUEBEC

H.G. ANSELL, A.C. ROBERTS rNo A.G. PLANT GeologicalSurvey ol Canada,601 Booth Steet, Ottawa, Ontario KIA 0E8

B.D. STURMAN Department of Mineralogy and Geology, Royal Ontario Museurn, 100 Queen'sPark, Toronto, Ontario M5S 2C6

AssrRAcr 40.8. total 99,5.La formule empiriquecalcul6e sur 7 atomes d'orygdne est Cao.seZro.erSiz.ogO",d'ot la Gittinsite is a new calcium zirconium silicate CaZrSinOz.Monoclinique. a 6.878(4), pegmatitic formule id6ale mineral found in lenses in a regionally b 8.674(4'),c 4.697(2\L, p tOLtq(4)o, z - 2, metamomhosed agpaitic syenite complex at the groupe spatial C2/m, la gittinsite est l'analoguede Kipawa River, Villedieu Township, T6miscamingue la thorveitite (PDF 19-1125). La densit6calcul6e grey-white County, Qu6bec. It forms chalky, fine- est de 3.624. grained intergrowths with apophyllite that. are com- (Traduit par la R6daction)' monly associated with vlasovite. Other associated minerals are eudialyte, fluorite, graphite, calcite, Mots-cl6s; gittinsite, nouvelle espdce, silicate de apatite, opal, agrellite, clinoamphibole, mosandrite, calcium et de zirconium, complexe sy6nitique pectolite. microcline and thorite. Colorless in thin agpaitique, riviire Kipawa, Qu6bec' propri6t6s section, gittinsite is biaxial negative with 2V, = optiques.analyse d la microsonde,diffraction X. 30(10)", n. 1.720(2). nu 1.136(2), n" 1.738(2), extinction on (010) being nearly parallel to the INrnooucrtoN X direction. at an angle of 5-100 to elongation (c). Electron-microprobe analysis gave CaO 18.4, In a description of the occurrence of vlasovite ZrO2 40.3, SiO, 40.8, total 99,5Vo. The empirical NaZrSiaOrr in thb alkalic co,mplexat the Kipawa formula calculated for 7 oxygen atoms is Cao.gr River, Villedieu Township, T6miscamingue or, CaZrSirOr. is Zro.eaSi:.orO? ideally. Gittinqite County, Gittins et al. (1973) reported monoclinic, a 6.878(4), b 8.674(4), c a.697(2\ 4., Qu6bec, the presence of a new unnamed mineral found P 101.74(4)o. Z=2, space erottp C2/m by analogy with thortveitite (PDF 19-1125), The calculated as an alteration along vlasovite cleavages.The densitt' for CaZrSi:Oz is 3.624 s/cms. mineral occurs as radiating sheavesof prismatic crystals 0.1-0.3 mm in length, too small to Keywords: new mineral, calcium zirco- sittinsite, permit of optical and physical nium silicate, agpaitic syenite complex, Kipawa the determination the crystals River, Qu6bec, optical properties, electron-micro- properties; the authors did note that probe analysis, X-ray diffraction. have very low birefringence. Electron-micro- probe analysesshowed that the mineral has an Solrtvrerns ideal composition of CaZrSirO'. In 1975 and 1976 the senior author collected gittinsite, La min6ral nouveau, est un silicate suites of mineral specimens from the Kipawa et zirconium. On la trouve dans des len- de calcium River complex and noted the presenceof some pegmatitiques d'un complexe sy6nitique agpai- tilles pods, zm in size, tique i m6tamorphiime r6gional prds de la rividre Ki- grey-white egg-shaped up to 2 pawa (canton de Villedieu, comt6 de T6miscamingue, in eudialyte-rich pegmatite lenses. In a prelimi- Qu6bec). Elle forme avec l'apophyllite de fines nary study of this material (Plant & Roberts intercroissances crayeuses d'un blanc grisitre asso' 1979), examination of thin sections of the pods, ci6es d'ordinaire i de la vlasovitq mais aussi using incident light, revealed a eutectic-like fine i d'autres esplces: eudialyte, fluorine, graphite, grained intergrowth of two phaseswith different calcite, apatite, opale, agrellite, clinoamphibole, reflectivities. Lenses of coarser grained material pectolite, mosandrite, microcline et thorite. Incolore are present within tle pods and consist of the la est biaxe n6gative, en lame mince. eittinsite same two phasesfound in the matrix (Fig. 1). 2V 3O(lOo), n- 1.720(2\. na 1.136(2),ny 1.738(2): showed that son extinction, presque paralldle i X, fait un angle Quantitative microprobe analysis de 5 i 10o avec I'allongement (c). Une analyse i the higher reflectivity phase is stoichiometric la microsonde donne: CaO 18.4, ZtOz 40.3, SiO, CaZrSizO" and that the second phase has a 201

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Frc. l. (a) Reflected light view of relatively coarse grained lens of gittinsite with enclosing apophyllite, in fine lrained intergrowth of the same two minerals. (b) Same view, transmitted lieht.

composition consistent with that of an apophyl- Occunnnltcr lite. SubsequentX-ray-diffraction study of the intergrowth confirmed the identity of the apo- Gittinsite is a very rare mineral found in phyllite and yielded approximate crystallographic eudialyte-rich pegmatitic lenses in a regionally data for the CaZrSizOr. Additional specimen metamorphosed agpaitic syenite complex at the material has since been obtained, permitting a Kipawa River, Villedieu Township, T6misca- more detailed study of the unnamed phase and mingue County, Qu6bec,latitude 46o48'30' N, its eventual characterization as the new mineral longitude 78o3O'20' W. [Geographic coordinates gittinsite. given in Gittins et al. (1973), Aarden & Gittins Gittinsite (eit'-tin-sit) has bee4 named for (1974) and Gittins et al. (1976) are not ac- poorly Professor John Gittins, Department of Geology' curate.l The geology of the complex is University of Toronto, who first noted its known; descriptive summaries are giYen in occurrence and reported it as an unidentified Gittins et aI. (1976) and Aarden & Gittins mineral. Dr. Gittins is well known for his con- (1974). tributions to the petrology of alkalic rock com- Gittinsite is always found in intimate asso- plexes. Both the mineral and the mineral name ciation with apophyllite and commonly, but not were approved prior to publication by the Com' invariably, with vlasovite. Other closely asso- graphite, mission on.New Minerals and Mineral Names, ciated minerals are eudialyte, fluorite, I.M.A. Holotype material is preserved in the calcite, apatite and opal. The names "apophyl- 'of National Mineral Collection, Geological Survey lite" and "apatite" are used in the absence of Canada, Ottawa, under catalogue number complete anilyses of these minerals. From their 19558. Additional type material will be depo- assoiiations, they are likely to prove to be the sited with the Department of Mineralogy and fluorine-rich members of both groups. Occurring Geology, Royal Ontario Museum, Toronto, and within the same pegmatite lens are agrellite, the Department of Geology, University of To- mosandrite, microcline, pectolite, thorite and ronto. clinoamphibole.

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'I. Puysrcel eNp Oprtcel Pnoprnrns TABLE T-MY DATAFOR GITT1NSITE

Gittinsite occunl as fibrous to radiating masses Iest d*, d"ul" hkl Iest d*". d"ur. hkl intimately associatedwith apophyllite (Fig. 1), in round pods with an observed maximum Cr cleavage planes 4,62 4.60 001 1.|.674 132 1 4,35 4.U o20 space group CZ/m. tinction with the principal vibration direction Gittinsite is considered to be the CaZr analogue X at an angle of 5-l0o to the elongation c, of thortveitite, in which two Sc atoms occuPy and Z and Y nearly perpendicular to it. Cal- different structural sites. culated from the chemical composition, the Gladstone-Dale constant Kc - O.2lO, and from AcrNowr-EncEMENTS the calculated density and measured indices of refraction. K" - 0.202. We are indebted to Ernest Nadon of T6mis- camingue (Qu6bec) and Ray Virtue of North Cnrrvrrc.lr Cottrostuox Bay (Ontario) for providing some excellent specimensof the gittinsite-apophyllite associated was obtained with a A chemical analysis with vlasovite. Special thanks are also due to Company electron micro- Materials Analysis Ernest Nadon, who gtaciously guided and as- probe, accelerating voltage operating with an sisted the senior author on his earlier expedi- specimencurrent of 0.03 p,A on of 20 kV and a tions to the Kipawa River occurrence. zircon. Using synthetic diopside (for Ca and Si) and zircon (for Zr) as standards, analysis RsrrnnNcns of gittinsite gave CaO I8.4, ZrOz 4O.3, SiO2 4O.8, total 99.5%, comparable with the analysis Aenonx, H.M. & Grrrns, J. (1974): Hiortdablite in Gittins et al. (1973). No other elementswith from Kipawa River, Villedieu Township, Temis- atomic number greater than 10 were detected caming County, Qu6bec,Canada. Can. Mineral. in energy-dispersivespectra. The empirical for- L2, 241-247, mula of gittinsite, calculated on the basis of 7 GITTINS,J., BowN, M.G, & StunMeN,D. (1976): regional- oxygen atoms, is Cao.sZro.eeSir.orOror, ideally, Agrellite, a new rock-forming mineral in agpaitic alkalic rocks. Can. CaZrSirOz. ly metamorphosed Minerql. L4, 120-126. -, Fr.rsr, S.G. (1973): X-Rev Powonn DrrnecttoN GasrARruNr,E.L. & The occurrenceof vlasovite in Canada. Can. X-ray single-crystal determinations could not Mineral. t2, 2IL-214. be made because of the small grain-size. The Pr-eNr, A.G. & Rorenrs, A.C. (1979): New data X-ray powd_erdiffraction pattern, however, was on unnamed CaZrSi2OTfrom Kipawa, Quebec. successfullyindexed on a monoclinic cell, giving GeoI. Surv. Can. Pap. 79-tl\ 391-392. a 6.878(4), b 8.674(4), c 4.697(2) A, B 101,74(4)o, Z = 2 by analogywith thortveitite, Receiveillanuary 1980,manuscript accepted Feb' Sc,SiaOz(PDF I9-t125). X-ray data are given ruary 1980.

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