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Gittinsite, a New Calcium Zirconium Silicate from The 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 Downloaded from http://pubs.geoscienceworld.org/canmin/article-pdf/18/2/201/3445777/201.pdf by guest on 29 September 2021 ,202 THE CANADIAN MINERALOGIST 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. Downloaded from http://pubs.geoscienceworld.org/canmin/article-pdf/18/2/201/3445777/201.pdf by guest on 29 September 2021 GITT'INSITE. A NEW CA ZR SILICATE 203 '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 <on r (n a.5a a.'a ll0 7 1.677 dimension of 2 cm and along cleavage planes 4,62 4.60 001 1.|.674 132 1 4,35 4.U o20 <a I.OJJ 1.634 241 I 1.6t7 r.._1.616 222' in vlasovite. No orientation relationship is ap- 2 3.78 3,79 Tll .;..1.604 I 3.232 3.232 lll .l 1.605 '1.578 T5l parent gittinsite The git- 021 I 1.577 042 between and vlasovite. l0 * 3.026 3,026 201 I 1,572 1.572 $r white I r tinsite-apophyllite intergrowths are chalky 2.60 2,660 ?20 '1.532 1.553 l5l hardness of 2.443 2.82 221 I 1 K12 nnt t in color with an estimated Mohs 2.385 2.385 13l* f r .516 203 3V24. The maximum length of individual git- ?.302 2.300 00?, I .514 I 1.513 vtoz 2.226 2.225 13la Lt.stz 242 tinsite fibres is approximately 0.1 mm, with a 2,1s8 2.157 2211 i<i 1.486 1.486 401 2.134 2.tU 3n* 't,446 f 'r.445l .446 060 length-to-width ratio approaching 50:1. The 2.108 2.109 2oz* 2 | 023 I 1.444 312 'r.9982.032 2.032 022' -r.43r small grain-size and intergrown nature of the <t 1.997 112 <i 1.432 223 1.414 ll3 * mineral precluded the determination of most I 'I1.961 1.961 041. 1 1.413 '152 .898 I .897 222' <l 1.389 fl.39o physical properties, including measured density. I 1.814 1,812 132i Lr.rg8 313 I 1.772 1.773 fl.377 I33 Calculated density for stoichiometric CaZrSizOr f./55 t.taa 331 1r.373 350 is 3.624 g/cm". 1.741 I .741 202' In section with transmitted light, git- thin 114.5m Debye-Scherrercarera, CuKaradlatlon' Nl.filter- tinsite is colorless. In reflected light, it has a frcur"=t.sqtz8R), fllm f50s00,lntensltles estlmted vlsually' apo- . jta rndexedwrth a 6'878 noticeably higher reflectance than that of ri"l:'r:[!i-fr:'l i:{:i8r*' phyllite. Gittinsite is optically biaxial negative, t^'-..i ZVo = 30(10)", n" 1.72O(2),np 1.736(2),nt' in Table 1. None of the derived Miller indices 1.738(2). The fibres show. nearly parallel ex- violate the requirements of 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.
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