439
The CanadianMine ralo gist Y oI. 32, pp. 439448 (1994)
HOGTUVAITE,A NEWBERVLLIAN MEMBER OF THE AENIGMATITE GROUP FROMNORWAY, WITH NEW X.RAYDATA ON AENIGMATITE RICHARD I. GRAUCH IJ.S.Geol.ogicat Survey,973 Denver Federal Center, Denver, Colora.do 80225' U.S.A. INGVARLINDAHL Norgesgeolngiskz undersqkelse, Postbol Mots-cl6s:hogfuvalte, nouvelle esp&e mindrale,donn6es de diffraction X, aenigmatite,Norvdge. - D.""*"d 1991- 440 TTIE CANADIAN MINERALOGIST IvrnooucrroN ical argumentsrequired for the proposalof hogtuvaite as a new mineral species.The Commissionon New Hogtuvaitewas discoveredin 1983by Ingvar Minerals and Mineral Namesof the International Lindahl during an uranium explorationprogram in the MineralogicalAssociation approved hpgtuvaite ProterozoicHpgtuva Window of the Norwegian (90-051) as a new mineral.Type materialis on Caledonides(Fig. l). The mineral megascopically depositat the Mineralogical-GeologicalMuseum, resembleshornblende, but has a slightly different University of Oslo, Oslo, Norway and the Smithsonian luster and cleavage.Optical, X-ray, and chemical Institution, Washington,D.C. examination of the phaseconfirmed that it is not an amphibole,but did not lead to an unambiguousidenti- OccunnsNcsarvl Gpotocrcar Sprrrnc fication. Considerableeffort was spenton single- crystal X-ray investigations,which were complicated The type locality for hogtuvaiteis approximately by ubiquitouspolysynthetic twinning. Identification of 7 km southeastof H6gtuva (a prominent coastal the pseudomonocliniccharacter of the phasebv mountain) and approximately 16 km northwest of HowardEvans led to the recognitionof its aisociation Mo i Rana,Nordland County, Norway @g. 1). The with the aenigmatitegroup. D.M. Burt's vector- approximatelatitude, longitudeand elevationare analysis definition of chemically permissible end- 66"24'15'N, 13o52'35"E and 400 m, respectively. membersof the group (Burt 1994)provided the chem- H6gtuvaite is named for the nearestsignificant EXPLANATION Foliation" amphibolite and biotite schist ID Beryllium qes- and t)"e locatiry ot hpgtwaite Frc. HOGTWAIIE, MEMBER OF TI{E AEMGMATITE GROUP 441 Fro. 2. Type samfle ofhogtuvaite. geomorphologicalfeature, Hpgtuva, which attains an units that host the hpgtuvaiteform one of severallarge elevationof L 268 m. A geological descriptionof the hecambrian windows in the Norwegian Caledonides areais providedin Lindahl & Grauch(1988). (Fig. 1). At least two poorly developedfoliations are Hpgtuvaite occurs principally as a late-stage, presentin the gneiss.The youngestfoliation apparent- poikileflzslis, metamorphicmineral in poorly foliated, ly developedduring Caledonianmetamorphism and polymetamorphic,peraluminous granitic gneiss.It is nappeformation. It i$ not known whether or not the concentratedand randomly orientedin planesof folia- Hogluva Window is autochthonous,but at least parts tion (Fig. 2). H4gtwaite constitutesup to approxi- of it were subjectedto metamorphicconditions similar mately L5Voby volume of the host gneiss.Minor to thosethat affectedthe surroundingPaleozoic rocks' amountsoccur in small, mafic pegmatitesof meta- Kyanite-staurolite-bearingmineral assemblagesin the morphic origin that crop out sporadically in the surrounding Caledonian metasedimentsand terrane. The h6gtuvaite-bearinggneisses are a minor biotite-garnet (quartz-free)rocks within the Hogtuva componentof an Early Proterozoic(l 700-1 900 Ma) Window suggestthe existenceof amphibolite-facies complex that hosts a small, strataboundberyllium temperaturesand pressuresduring the crystallization deposit.Hggtuvaite has beenused as an indicator of hpgtuvaite in the young foliation planes of the mineral for beryllium ore that consistsof phenacite- Precambriangneisses. The lack of appropriatewhole- rich gneiss.In addition to beryllium, the gneissesare rock compositions(such as those of pelites) in the unusually enriched in the rare-earth elements(espe- HAgnwa Window has hamperedthe determinationof cially the heavy rare-earthelements), zirconium, the exact metamorphicconditions in which hogluvaite uranium, fluorine, and tin. Minerals associatedwith formed. hogtuvaite include quartz, albite, microcline, biotite, phenacite,zircon, fluorite, calcite, chlorite, magnetite AppuARANcsAND PHYSIcAL Pnopnnrres [commonly with lamellae of pyrophaniteand, rarely, cassiterite,according to Grauch& Lindahl (1984)1, Hpgtuvaite forms prismatic black cry$talsup to and minor amountsof gadolinite,danalite, genthelvite, 4 cm long, with a maximum diameter of approxi- allanite, titanite, pyrochlore, thorite, uraninite, mately 6 mm. Crystalshave well-developedstriations fergusonite,euxenite, kainosite, tlalenite, yttrialite, parallel to the axis of elongationand a pronounced fluocerite, wolframite, apatite, sphalerite, galena, parting approximatelyperpendicular to that axis. The molybdenite,chalcopyrite, arsenopyrite, and pyrite. crystals generally occur as individuals, but radiating Our understandingof the conditionsof formation of groups of tlree or four have been observed(Ftg. 2). hOgtuvaiteis basedon indirect evidence.The gneiss The poikiloblastic nature of hpgtuvaiteis megascopi- 442 TIIE CANADIAN MINERALOGIST Ftc. 3. Thin section of gneiss host of the type hOgtuvaite(euhedral, black crystals). Matrix is predorninantlyquartz, phenacite, biotite, albite, and microcline.Plane- polarized,transmitrsd light. Field of view is 4.6 cm wide. cally observableand readily apparentin thin section OFncAL PROPERTES (Fig. 3). The physical propertiesof hOgtuvaiteare summarizedin Table 1" and contrastedto those of Becauseof the nearly opaquecharacter of hOgtu- other membersof the aenigmatitegroup in Table2. vaite, its optical properties have been incompletely The difference betweenthe measureddensity, determined.Ultrathin sections(<10 pm in thickness) 3.85 g/cm3,and the calculateddensity, 3.98 g/cm3, were usedfor the optical deterrninations.Hpgtuvaite is may be attributedto the ubiquitousinclusions of biaxial negative(?),with a large 2V. Pleochroism quartz and other phasesand to the difficulty in estab- is very strong, ranging from bronze to grcen. Indices [shing accurateand completecompositional data for of refraction (d L.78 nd ( 1.82) were estimatedby the grainsused in the measurementsof density. the reflected light, two-media method. Reflectance TABLE 1. PHYSICALPROPERTIESOF HOGTIryAITE FROIVINORDLAI.ID @uNTr. NORWAY Colon Black SEeak"Mgrcen Iarsten Nmmetallic,subadamad@ Transparency:Opaqng 0o sbtransbc€tr Fluorescence:Nsre Hsdtess: 55 (Mds) Oeavagu T*o gooddirectios at abqrt 55' Pdting: Impqfect prtiag, ryproximatelyperpdicular to lb axis of elongation Tenasit'': Bdftle Fracmre:Uneven D€osity(mea$rod): neasrod): 3.85(.O2) e/cm3g/cmr (Ctcici solutim); 3.853g/cm3 Gy@neter) (calcplaFd): 3.98g/cm3 (using V;=730.4 A3, mue8?4.Wgd7Fzl tvlagreticNo Reactimto acidsad bases:Hogbvaite is not obviorslyatresbd by oold slfuio api4 acetic acid,Edrocnorio aciCIdtric arid, perchlodcaci4 arya regia ammmiumhydroxie, sodiumtydroxide, o potassiunhydroxido. It does dlssolveslovly ud withmt effenrcsg@ in cold hydrofluoricacid. HOGTWAITE. MEMBER OF THE AEMGMATITE GROT]P M3 gtgEgii"$,t$$g€isi ;; li$;;$i[i o* ':€ !RB ":e €h -\--e g tstsF e: 9; -.: iE Q gnuu $:- J :9qq viFiv! I ;?Y? l:;?{ r hl 3h BfiE€ "qEq" x- sssiHic"rr$$eoiddo !9o 2 iaEii lii c$ ag .jt : i? p j: {'i >.H ^off s> ; s ^e':qc3 d- :jj Fr ' ..i ,.: :d sod cd oi ve F H t: FS r :gffi3i:":ffi{€ !6 .Ee H ls hE o .gq z oodc orEoo I t 5 I Ea Yioitq \"!!i6lg !8 OOaOOOg$rgi-E f e hbo- on-OO ;E .38 irii; c!9qthbFF 6iSdi o? "i[*[;[l"i:{; lqqqq O-dO OINOo 5h a g g t! Irl i qo t-1 .Ee 8c lil E a* 56 ot 6$Q.c oBqrs dO {iii T?TTq'a .i .i hEEiEi!$-:'i riI €a$E -o\Foo:sHqE lr\ i ft igEigr$ilgt:--i:;ix 96:- I3f; rl g a ai Etr 3 s! b F €_aa < o6 ,rre TBT?Y{$q$ .t- € ocrSe $qqSq .EC6 =ggigrii"i'i tE- i sli'{gili ii Ci3G doovio EIi ${r i'E i'c I o; - o;€ k=v6 ..^.^:^ 0 H3*; $ . r ec . iQ€l* r.crSn^ E ! : jX X $rxl; od9..:c *'i F5E ![[[i[["*'$s r .EE'6i'; { Ee!* F,9€Y fr lilA ! 6I1 ?o q > N t.: ii F $g**eisry"g{*;€-E,-'g*U*s$$$$3$srs$seE}} z?H> & zdt; *, 444 TIIE CANADIAN MINERALOGIST measurementswere made with monochromaticlight Major components(Table 3) were determinedby (540nm) in air andin immersionfluid (n5a6= 1.518). ICP by J.G. Crock and J.L. Seeleyat the U.S. Calculatedabsorption-coefficients for the a' and^( GeologicalSurvey, using the techniqueof Uchte et al. directionsare 0.31 and 0.28, respectively.The (1987),by electronmicroprobe, or by bothtechniques. reflectances(in Vo)in air and oil are Ro, 9.05(10), FeO was determinedat the Norgesgeologiske under- i'V V.32(8), andi-\, 1.48(4),and l.5l(4). Enors sgkelseusing tle techniqueof Graff (1983) and at are2c, basedon l0 measurementsiri eachdirection. the U.S. GeologicalSurvey by E.L. Brandt and The optical propertiesare similar to those of rhiinite, L.L. Jacksonusing the techniqueof Peck (1964).No but distinct comparedto thoseof other membersof the significant differencesexist in the two data sets.The aenigmatitegroup (Table2). concentrationof beryllium was determinedby ICP. The major-elementcompositions of hpgtuvaiteand the CIDMISTRY other membersof the aenigmatitegroup are compared andcontrasted in Table2. The simplified formula for h@gtuvaite, Mijssbauerdetermination of Fe3+/Fe'*by D. (Ca,Na)r(Fe2+,Fe3*,Ti,Mg,Mn,Sn)u(Si,Be,Al)6O26,is Sherman using a simple two-doubletfit to the derivedfrom the empiricalformula (Ca1.6Nao.n)2r.ou M0ssbauerspectrum yielded a valueof 0.618.Using a (Fez+.r.orF e5+r.e6Tio.r9Mgo.orMno.s3Sns.e3):s.ss(Sia.oo more complicatedfour-doublet fit, the value is 0.59. Beo.e2Als.a5)>5.e7O2s.The empirical formula is based Both are in excellentagreement with the value,0.61, on the averagecomposition (Table 3) of four samples obtainedby wet chemistryand inferred from electron- of gneiss-hostedhogruvaite (N82-70, N86-lA, microproberesults. The Mdssbauerdata suggest mul- N86-lB, N86-3). Samplesanalyzed by wet chemistry tiple sitesfor theiron. and inductivelycoupled plasma - atomicemission The concenrationof trace components(Table 3) spectrometry(ICP) consistof splits of hand-picked was determinedby ICP. CoulometricKarl Fishertitra- fragmentsof crystals.The fragmentswere generally tion (Jacksonet al. 1987)was usedby L.L. Jackson; lessthan half a millimeter in long dimensionand were no structuralwater was found. That result confirms as free as possiblefrom inclusions.Samples analyzed thermalgravimetric analyses (TGA), which show by electron microprobeare from three different hand about0.25Vo weight loss (adsorbedwater) at 100oC samples.Two of the compositionspertain to the type and minor weight gain (oxidation of iron) at approxi- specimen(N86-lA and N86-1B); the other two mately 800'C. Electron-microprobeanalyses (wave- (N82-70 and N86-3) are of samplesfrom the type lengthdispersion) showed the absenceof fluorine, area. phosphorusand potassium.Energy-dispersion analy- TABLE 3. CITEMICALCOMPOSITION OF HOGTWAITE FROM NORDLANDCOTJNTT, NORWAY Sampleno. Hogtuvaitet NE2-70 N86-lA NE6-IB N86-3 N86{B Hostrock Seiss gneiss grreiss gneiss pegmatite N*,f 37 26 25 28 25 sio2 3t.60 32.2114.773t.51+f.74 31.5310.5831.04+0.79 32.t5*t.t7 AlzQ 2.64 2.221{.32 2.75t{.t6 213rfi.tt 210+t.29 0.93+0.25 BeO 2$5 2.47 2.83 Fe203 t9.03 1E.87 20.02 F€O 28.06 28.U 27.41 FefO 45.42lJ69 45.4A2.48 45.23+1.3845.58*l.2$6 44.7t*t.49 riq 2.77 3.7418.27 2.2U4.12 2.2644.t9 2.62A.37 4.r7a{..23 SnO2 0.53 0.49 0.50{.17 0.54+0.16 0.53a4.13 0.1610.05 MnO 0.27 0.2A 0.29+0.09 0.27fi.07 0.28+0.0E 0.52*{.07 Mgo o.42 0.50$.19 0.46+0.10 0.43+0.12 0.29J{..06 CaO to.44 10.?2+0.3Et0.97r4.34 10.92+0.25l0.E?d{.51 10.16$.33 Na2O 1.52 l.3l+0.20 1.34+0.15 1.37+0.25 I.?E+0.19 TOTAL 99.93 99.36 100.49 95.28*1.5595.42i!1.83 94.87*r.96 r ThisisttnpreferrodcompositionofhOg[naito,basedmanalyticalrffirltsobtaincdmgEirs- hostedsamples.t* Nisfbnumberofanalysesperfcmed.Erro8arelo; &eyarenotlepot€d rviere thenumber of analysasfor a specificetrement is insuffici€ntfor reasoablestatistics. The propotior of FerO, is detemriredby difruencebetee€n lotal Fe andFeO. Fe,O is frg tobl Fe calculatEdas FeO. Tracecomponents of N86-l (determinedby ICp andquotEd in ppln) ue: B 95,Ba 10,Ce 3J0, Cr 5, (} d, (tt ?.6,8t t.s,Ho 44,La l4S,Li 50.Nb 1,110,Nd 165.Ni <10. Pb 170,Sc 5, Sr 35, Th 570, lJ 2s,v 23. Y 12S0,yb 410, andZn 520. HOGTTJVAITE.MEMBER OF THE AEMGMATITE GROTJP M5 ses did not detect any elementstiat were not sought order to adequatelyrefine tlte unit-cell parametersof by other methods. h6gtuvaite,the powder data had to be preindexedon No significantcompositional variations were the basisofintensity valuespredicted from the closely observedwithin single crystals or betweencrystals in related structureof aenigmatite(Cannillo et al. l97L). the samepolished thin section.Only minor variations In this way, 28 20 values could be unambiguously exist betweencrystals from different gneiss samples. indexed,and thesewere usedfor least-squaresrefine- However,hpgtuvaite crystals from a small, mafic ment of the triclinic unit-cell constants.The powder- pegmatiteof metamorphicorigin (Table 3, sample diffraction data were measuredfrom Guinier-Hiigg N86-68) exhibit minor variations in the same patternsmade with CrKcrr radiation (),' 2.28970A), polished thin sectionand are significantly different which providedmaximum resolution of the diffraction from h6gtuvaitein the gneisssamples. The pegmatite- maxima. In order to adequatelycompare the powder- hosted samplescontain more Ti and Mn, and less Al diffraction patternsof hogtuvaiteand aenigmatite,we and Sn, than the gneiss-hostedsamples. These varia- had to generateunequivocally indexed powder- tions may reflect variationsin host-rockcomposition diffraction data for aenigmatite.The data were and are to be expectedbecause of the large number measuredfor aenigmatitefrom PantelleriaIsland, Italy and variable sizesof cation sitesin aenigmatite-group (U.S. NationalMuseum of Natural History, No. minerals. C2580),and47 20 valueswere used to refinethe unit cell of that mineral. The resulting unit-cell data for Cnvsranocnapnv both aenigmatiteand hpgtuvaite are given in various comparativeorientations in Table 4 and are compared X-ray powder-diffractiondata for h@gtuvaite to the other membersof the aenigmatitegroup in closely resemblethose of the other minerals of the Table2.In orderto emphasizethe differencesbetween aenigmatitegroup (Table2). As shownoriginally by the minerals, the unit-cell data were calculatedusing Kelsey& McKie (1964),this group of mineralstypi- the conventionaltriclinic setting defined by Kelsey & cally is riclinic, but has a crystal structurethat is McKie (1964).The observedand calculatedpowder- metrically close to being monoclinic. Therefore,in diffraction data for hpgtuvaiteare given in Table 5, and the new data for aenigmatiteare given in Table 6. The data for aenigmatiterepresent the most complete and rigorously indexed set of powder-diffractiondata availablein the literaturefor that mineral. TABLE 4. IJNIT CELLS FOR HOGTWAITE AND AENIGMATITE DrscussloN Mineral t{sgtuwits Amig@tite Ielity Nordlud Courty, Nomy P0tellqia Isl@d, Italy The crystallographyand crystal chemistryof h@gtu- Conventionaltriclinic uit cell., spu group PT vaite, as shown by analogy to the crystal-structure ro.3l7(l) A to.4t7 (2) b t0.724(r) r0.817(2) analysesof aenigmatite(Cannillo et al. L97l) 8.855(l) 8.92e(t) and rhdnite (Bonaccorsiet al. 1990),are extremely q 105.770F 104.86(r) I e6.21(l) .77(2) complex.The structuresare basedon complex alumi- ru.77 (1) t25.54 (2) nosilicatechains, consisting of pyroxene-likechains z:o.q(r) Ar 74s.8 (2) with extra tetrahedraattached alternately on opposite Psdomoaolinic uit @[', sp@ group Af sides,having the composition[T6Ors]n. The structure 11.908 12.144 29.621 (Cannillo et al. l97l) containssix tetrahedrallycoor- 10.317 t0.416 dinatedsites, seven octahedrally coordinated sites, and c 90.00 89.85 eachsite is p t26.44 127.24 two 7- or 8-coordinatedsites. Although 'f 90.03 89.83 structurallydistinct, the chemicalcontent is not unique and consistsof mixtures of various cations,which are Reduc€dtriclinic unit cell,, sprc group PT a 8.855 8.930 generally assignedto each of the three types of sites b 9.760 .9.734 accordingto their characteristiccoordination-numbers. 10.31? 10.416 n4.39 ll4.3l Thus, the formulas ofthe group are usually reducedto p 96.2r 96.77 in whichA = Na,Ca; M =Mg,Fe, .T LAl2LM6O2llT6O1sl, 64.50 64.98 Ti, Mn, Sn, Sb; Z = Si, Al, Be. H@gtuvaiteis distinct as a separatemineral on the basisof its relatively high Note: Unit-ell pmet6 w derivedby lsst-squs ualy3is of powdq data 7 Aom Tabls 5 md 6. Be content,which is sufficient to correspondto one ' Correntional ticlinic rening definedby Kelsey& McKie siteper formulaunit. SeeBurt (1994)for a discussion 'Psdomonmlinio O964). cell of Cmilo et al. (1971),origin centeBat 0,0,0; 0, l/2, of the permissiblecomposition-space of hogtuvaite 112',rf2,l/4,ll4:'1,,,314,3/4. Thisis theM ell ofMolino (1970). Tnndom eflentional to monmlinic ell by: 0ll/-1, -2,Arc0. and the aenigmatitegroup. Table 2 summarizes,com- a Staodud redqaeduit ell Mghell I 976). Trosfom @nvedionalto reduc€d pares,and contraststhe physical and chemical differ- e[ by: 0Ol/l l0/100. encesof the aenigmatite-groupminerals and clearly 446 THE CANADIAN MINERALOGIST TABI,:E5. FOWDER-DIFFRAC'IIONDATA FORHOGTUVA1TE FROM NORDI,AND CICUNTT' NORWAY htt dcalc I@b dds lobs 2&bs hkl dale lcrlc dobs tds 2&SB 0l &042 ?t'l 8.048 90 16356 44 0 u\n 23rM 3 59.rm 00 &035 e ) 42 2 ur% 4l 0-l 7.3W 13 738E lJ l?.830f 4L 0 uw 23068 13 60509 l-l 6346 16 6353 L3 ?AJ65S 4-2 t 23064 nl 01 4,Tn 44 u%a n.@Lt o4 Lt9t4 ol Lt9t4 3 6LW o-2 4.383 4l 4.385 3 30268 0-2 2.1898 6l 0-1 4380 3 I 44 I 2.1800 z.tw 3 6336 -20 4.1?5 121 4.1?8 13 3lJ10 43 2 7-1798 0-4 LLTOI {'l 2.L66 2 63,f,?9 4.114 t2 ) :l 3J63 t7 \JA $ 35.411t 0-1 2.t63 0-2 3.695 30 3,@5 19 36.W8 3-5 L1402 J 2.t394 3 @3e6t -l 3,435 30I 3.435 r',l 38.943 0 2-125 6 Llut 5 65zns -al 3.431 31I 24 1@E0 70'l L@',19 63 6.145 l1 3350 2 3345 E 40.034E -20 L@6 6l 3246' 5 3A1 2 41291r -40 L&J74 el 2.W7L L0 6f,533 321 1 3n 2 41.633s 44 L@69 ltl q 10 3.169 2 3.18E 3 ALc,ff 4-t Lot50 6 Ln41 &gfr',r 3.175 I I 3,t'16 4 42261 40 0 1.980 4l 1.9973 3 69.9218 3.n3 2 ) \ryl4 al o2 3.tD, A1 3.tx 6 4\X1 -25 0 1.9&16 lel L.WA 10531 01 3.121 5El 1.W2 19 I 'l -52 1967E3 71.63r -l -2 3.055 3.057 s 43.w 0 1.9619 5 'tLOt6 -2 -l 2,98r'.t 21 2.98/7 1 45.rLL -2 -4 2 1.94E2 41 t.9472 6 2s834 1 J 21 4 1.946/9 3-3 2-q721 7 2.8n2 5 4s.?94E 44 1.9390 A r.%9r 10 72376 292rB 621 Lm41 59 &W -2 1 1 t.w1 ol r.w35 4 73.96 0-! 2,9244 63 J 2 -2, t.w32 7l -33 2gtrta N 260E4 3 48.163 45 1.E758 6l Ift59 6 75.W -1 2 Ln6 n e704 l0 48318t 43 rst53 6_l 3-1 2:tw 5L 21550 n 49.L@s r&tl t L8/.2ri 2 76&4s L7tt3 tL 2X,18 t0 49.w8 40 1JOJ5 AI'I 1t029 8 78,E40 24 2.6758%l 2.6'161I fr.65'l 4-l 1.S32 4l -20 2.674 X I rntl 4l 1.704 E 80J82 30 LffiE 26646 18 50891t 3-6 t:fl06 3l 14 25/60 ll u& 9 53.4?r'8 14 t:1562 J 1.7560 3 81.@t 24 xa4 741 1.7355 11'I 1.7349 t3 8256r 42 25'93 rfi | 2S,'3L@ 53.W a-a (1352 1l -2 -l 252s 74 0-5 ''t79 5 1.7163 8 83.67E J 't -1 I 25172 14 23t57 54.148 l4 0 t7123 2 1.7118 5 83952 x053 13 25c62 6 y3568 -<4 0 r.w6 I txvlo 2 vzr78 0-3 L4633 6 LM 14 55374 t.7@ 2 t.1w 2 uslf al 2"4547151 145Jr 9 J5J91 at a t.6'149 2f 20 L4*r 15 | 2L 5 t.6'146 3l t.614L 8 86.a3 -2 -2 2.4t6 n 56.Jrc 1.6.141 6l L4rL4 381 gt.Xr 2-A 2.W7 40 ) -65 0 1.6550 41 t.f647 3 o2 23949 m 23951 5 5?.110t -63 1.6t50 4J -Jl 2,y.50 9 23442 E 5&,|695 0-5 1.61S 211 1.6191 33 89-994 -1 4 2.1244 8 23Ar 6 58.995 0-4 5 1.61E42rl ,& B f tu mv€d@l tirlidc mit-€tl Clable4); d+alqs (A) €lctrbed fc bidinic €lL tols hbsitis €ldlared tu tu ;oignatibs6u!6s. d-rnlq oogood" demonstratesthe uniquenessof hpgtuvaite.Without rating.Potential causes for achievinga rather resultsof a crystal-structureanalysis, it is not possible than "excellent"or "superior"rating include: (a) the to know the disribution of Be over the six Z sites,but indices of refraction calculatedfrom reflectance the divalent Be cation may be expectedto concentrate measurementsare, at best, approximate,(b) there is a in Z sitesassociated with the Ca2+ions in the A sites. problemin determiningthe actualdensity of hBgtu- Determinationof the crystal stnrctureof hpgtuvaite vaite, and (c) intervalencecharge-transfer Ge2+ - Fe3+ will be considerablyhampered by its intensepolysyn- and possiblyFe-Ti) is suggestedby the Mtissbauer thetictwinning on a twin axis normalto the (010).oou measurementsand may negatethe use of classically plane, which correspondsto the lateral faces of the determinedGladstone-Dale constants. crystalblades. Late in the preparationof this paper,we learned The compatibilityindex (Mandarino 1981) provides (Jambor& Vanko 1992)of a new mineral named a methodfor testingthe intemal consistencyof empiri- 'omakarochkinite"described by Yakubovichet al. cally determinedproperties of minerals.Specifically, (1990). Their careful crystallographicand chemical it tests the compatibility of the mean index of refrac- studiesleave no doubt that their informally proposed tion, density,and chemical composition. The compati- new mineral, which occurs in a ganite pegmatitein bility index of hpgtuvaiteis 0.052,which is a "good" the Ural Mountains,is the sameas hogtuvaite. HOGTWAITE" MEMBER OF TIIE AEMGMATITE GROUP 447 TABI,B6. POWDER-DIFFRACTIOI{DATA FOR AEMGMATITB FROM PANTEIIERA ISITND. ITALY hkl tub i6lt dobs fobs 2&bi hkl delc /€Ic dobs lobs 2&b 00 8.118 U I 8.121 58 16iXE3 u532 4l 01 8174 n ) 4-2 2316 12 \31cf 14 59.ig28 10 1.vB 1.vu 16,488f 239t2 It 23ffi2 14 595z7t t-l 6.K't r5 6316 6 a.68d 2n& 4l ..n17 4 6a.036 ^l 01 4335 45 4A19 I n.& 43 22t3 r-l 0-t 4.q7 41 4.398 6 3lt 175t LvA 6l 2-t944 2 6284 0-2 4386' 4) 0-l 2.rca {l 2-2 4.t9 11 4.t9 l, 31.6448 3-5 2.1643 2"t647 4 63,85Ds -40 4.184 t2 4.19 12 3l.7l8t -20 2,lm 7L 2.123432 62ilt 3Jn t7 3.7E1 352503 ,-5 2.rt62 71 2.1178 40 65./U88 3J@, 29 330/- n 36.0053 44 LW' 11 2.W4 4 6.@4t 3.s3 n1 3.491 t2 38291 40 2.W)l 9 2.s2. 6 ff,3518 J3 3.487 30I 4-l 2,gr3l 6 LVT28 I 61.648 -Jl 3n0 5 3nr 4 10.qnE 2'ol n L0rn fi 693ns 3.1$' 58 3.$3 n 423ns 45 0 LW n 2.@69 10 69J63N o2 3.145 62 3.L6 2n 4\(854 44 , l.E/86 n 19789 l0 70.695t -t -2 3053 1 3.055 16 44.0103 -52 0 19738 t9713 4 m s 3-3 29E71 6 3.W3 4 44.863t -30 r.9@ ;l 29755 18I 2.n45 6 45n4 4-5 1.9566 t9551 4 7l'ffi -2, 3 2gtr6 t7 J 2-A 4 19551 tl 0-l L9479 6X 294n A 45J@t l-t t.9441 1.9449 6 n.tB a 0-3 29@ 6l ,.9!2t 2, 453f.4'E -2 -3 t9432 r) 2-l 29264 U1 2-9L% 6 46.n4 43 3 1.9125 6'l 19112 8 73598 2l 29Br D J 2-2 191t8 7l -33 286ffi A 2&X2 L2 ',r.Lgls 45 t 1.9106 6l -t2 2A1n n 28144 6 4&m68 l0 4 t.&44 r1 r.fl90 2 ?8.01d 42 23625 t9 L7628 6 8.9d 4 t.Etg) 3l 3-1 2;t5K fi L7529 26 49.149s -25 I l.8ri5 4J -20 L706,2yl 27(b8 ?6 s0.63t 3-6 l.?84{t 3l Lrm 2 W.LBI 24 \7W yl 2.7@8 16 50.121x )-l 4 1.7i8t 4) ?n 235n 29 1656t 10 51.0523 -5 I 3 l1q t 1.7521 I 81J98 -34 2JSl 1l 25!@, t0 52.W? 5-3 a 1.7505 ti496 I $JA t-3 LXtl t4 $.WE -40 4 ttry1 1l 24 254/.1 741 2J4r9 100 53J38 LJ465 2) -a -l z.vB n I t34t5 6 rJ4t7 E 92.L938 42 2S4A L@) -2 -3 t3373 7 ljr3n I v.4n6 25tV, 13 25W2 I y.,g2t 0-1 LJ3N. 5 r'39 2 A.696 20 L45n $1 2,4568 6 55J50 0-5 I htQ 5 r:tur 2 91336 al L45?5 rs ) t67 6 1.6?98 6 EA. 8 2-2 14186 rlo'l L417918 521 -65 tj?59 a'l'l 1.675L E o2 L4r?j m ) 43 tj,747 Sa[pb nm U.S.Nali@l ldlsm of Natml lffsGt, spccim m, @580.i, &, I fo matioal tlplidc uit-cll Clat'ls4). arahs (A) elgnard fc ticlhio ell t(€lc) im@ddes0aloila&d tu aldgmrits stncbB {C@ilo a al 1971)h Df&d Eit-dl Cfabb 4), d deuned ftm t&bs vahs. I!!@siti€sm€ar@d witb N6i!s M@l tr l/fim{tribn€t{. 20 vafm |lwr€d vft Ntu Ftlm Viem o a C{hier-Higg pa!@ madevirt (tfql Edidi@ (r, 21892 A) ma a S t*t stadfid. $ Tndicd6 whes E€df6l€ast-{qm Enlmrddudt-sl Darctm. ACKNOWLEDGEMENTS RprsnsNcEs We thank the analysts,listed in the text, who BoNAccoRsI,E., Menr,wo,S. & Pasnno,M. (1990):Rh6nite: were very instrumentalin defining hogtuvaite. structural and microsfucoral features,crystal chemistry Specialthanks are due David M. Sherman,formerly and polysomaticrelationships. Eur. J. Mineral. 2,203- of the U.S. GeologicalSurvey and currently with 2r8. Battelle Corp., Richland, Washington,who is Bunr, D.M. (1994):Vector representationof somemineral responsiblefor the Mtissbaueranalyses and provided compositionsin the aenigmatitegoup. Can.Mineral.32, insight into the crystal chemistry of hogtuvaite. 449-457. John White, U.S. National Museum of Natural CaNNrr-r-o,8., Mrzzt, F., FANG,J.H., RoBNsoN,P.D. & History, provided the sampleof aenigmatite.We also OHvA,Y. (1971):The crystal structureof aenigmatite. thank J.A. Mandarinofor many useful suggestions, Am. M i nera l. 56.427 -446. M.B. Dugganand A.R. Kampf for constructive CoscA,M.A., RousB,R.C. & Essexe,E.J. (1988):Dorrite reviews, and R.F. Martin and R.C. Rousefor editorial [Car(MgrFe3+/(A14siro20],a new memberof the aenig- suppon. matite group from a pyrometamorphic melt-rock. Arr. M ineral. 73, 1440-1448. M8 TIIE CANADIAN MINERALOGIST DEER,w.A., Howrs, R.A. & ZussueN,J. (1978):Rock- County, Norway. In Proc. SeventhQuadrennial IAGOD Forming Minerals. 2A. Single-Chain Silicates. Iohn Symposium(Lute6, Sweden) (E. Zachrisson,ed.). Wiley andSons, New York. E, Schweizerbart'scheVerlagsbuchhandlung, Stuttgart (s83-594). Duccar, M.B. ( 1990):Wilkinsonite, Na2Fe2*4Fe3+2Si6O20, a new member of the aenigmatite group from the Macunq,M.P. & SUssE,P. (1974):Serendibite: a new WamrmbungleVolcano, New South Wales, Australia. memberof the aenignatitestructure group,Neues Jahrb- Am Mine ral. 75. 694-701. Mineral., M onatsh.,435 -447. Gnarr, P.-R. (1983): Determinationof FeO in geological MANDARINo,J.A. ( 1981 ): The Gladstone-Dalerelationship. mateials.Bull. Nor. Geol.Unders.38E,9-12. IV. The compatibilityconcept and its application.Can. Mineral.19.441-450. GRAUcH,R.I. & Lwpan, I. (1984):A uniquesuite of Sn- and Fe-Ti-Mn-Zn-oxides from Precambrianbiotite MERLTNo,S. (1970): Crystal structureof aengmattte.Chem. gneisses,Nordland County, Norway. Geol. Soc. Am., Com:tnun. 20. 1288 - 1289. Abstr. Pro g rams 16, 523. (1972): X-ray crystallographyof krinovite. Z. JAcKsoN,L.L., Bnowrq,F.W. & NEL, S.T. (1987):Major and Kristallogr.136, 8l-88. minor elementsrequiring individual determination,clas- sical whole rock analysis,and rapid rock analysis:/r MrcmlL A.D. (1976):The reducedcell: its usein theidenti- GeochemicalMethods of Analysis(P.A. Baedecker, ed.). fication of crystalline materials.J. Appl. Crystallogr. 9, U.S.Geol. Surv. Bull. L770,Gl-G23. 491-498. Jeunon, J.L. & VANKo,D.A. (1992):New mineral names. MoonE, P.B. (1978): Welshite, Ca2Mg4Fe3'Sb5*o2 Am-Mineral.77,M6452. [SinBe2O'3l,a new memberof the aenigmatitegroup. M ineral. M ag. 42, 129- 132. Joril.rsroN,A.D. & Srour, J.H. (1985):Compositional varia- tion of naturallyoccurring rhoenite. Am. Mineral.70, OrsEN,E. & Fucrs, L. (1968):Krinovite, NaMg2CrSi3O16: a r2rt-1216. new meteoritemineral. Science t6I,786-787 . KELsEy,C.H. & MCKIE,D. (1964):The unit-cell of aenig- PEcK,L.C. (1964):Systematic analysis of silicates.U.S. matfe.M ineral.M ag. 33,986- 1 001. Geol.Sun., Bull.1170. LrcHrE,F.E., GoLrcHrLy,D.W. & Leltorrm, P.E. (1987): YAKUBovrcH.O.V., MALINovsrn,Yu.A. & Polvarov, O.V. Inductivelycoupled plasma-atomic emission specffo- (1990):Crystal structue of makarochkinite.Sov. PWs. metry. In GeochemicalMethods of Analysis (P.A. Crystallogr.35, 818-822. Baedecker,ed.). U.S. Geol. Surv. Bull. l770,Bl-810. Ln\DAHL,I. & GRAUcH,R.I. (1988):Be-REE-U-Sn mineral- ReceivedFebruary 3, 1993, revisedmanuscript accepted ization in Precambriangranitic gneisses,Nordland August18, 1993. mineral, hostedby hoterozoic granitic gneissei-d -afi" pegmatitesof metamorphicorigin Compositionalvariations withirr and betweengneiss-hosted samples of Ipgtouat" are minimal; however,p"gmatir"-ttort"i samplesof hogtuvaiteare significantly differen! goo]alllnq le-ssAl and Snland more Ti and Mn, than thoie tim tne gneirro. Tde of tpe h6gtuvaite(invt,Vo) is CaO 10.44'Na2O 1'52, "o-position Hogtuvaiteforms reb zS.OO,Fqo3 19.03,TiO22.77, nago O.Iz, Mno 0.27,SnQ O.S:,sio2 31.60,Beo 2.65,*ou2.Y. black, elongad, poimofU.ti" ..ystals. It has a dark greenstreak, an unevenfracture, two good cleavagedirections' and a non- metallic subadamantineluster. it is nonmagnetic,ii not fluorescent,and does not react to most common acids and bases' However, it doesdissolve slowly in cold hftrofluoric acid. Its measureddensity is 3.85 g/cm3,and the calculateddensity is i.SS g!"d.The mineral is opaqueto subtransparen!biaxial negative(?) with3 large 2f, strongly pleochlgig@rgAJg"gfq anOtilso t.Zgand/1.82.itistrictlnic(pseudo-monoclinic),ipacegroupPT,withal0.3lT(1),b10.724(l),c8.855(l)A'a polysyntheticalll-Ygd:9" 105.77(1f, p 96.210)., \ 124.77(l)",Vin.q1) L3, andZ = Z. en sample9are {rtensely srrongesiseven X-ray powder-diifiactionlines td in L@(hkD1 are2.5293(100)(420), 8.048(90)(010)' ?.0979(63)(251), 2.gi7(5g)(031;Z3ieigA1ilt),2.0747(4T@nJ and3.125(46)(021). A new anduniquely indexed set of_X-ray powder dif- fraction datafor aenigmatiteis presented.The namehggtuvaite is hspired by the highestpeak near the type locality. Keywords:hggtuvaite, new mineral, composition,X-ray dat4 aenigmatite,Norway. Sotwtarne La hogtuvarte,essentiellement (C4Na)2(Fe2+,Fe3+,Ti,Mg,Mn,Sn)6(Si,Be,Al)6Ozo,_est un nouveau membre du groupe de laenigmftte, d6couvertdans le comt6de N-ordlanden Norvdge.n s'igit a'un mindratm6tamorphique faisant partie de gueiss granitiquesprotdrozolques et de pegmatitesmafiques d'origine m6tamorphique.Lesvariations dans sa cornpositiondans un &hantillon ou entre fchantillons ite"gneisssont minimes; toutefois,la hOgtuvar'tedes &hantillons de pegmatitecontient moins de Al et Sn, et plus de Ti et Mn. La-compositionchimique de la hg$uv;irc type (%,-poids)est: CaO 10.44,Na2O 1.52' FeO 2s.06,Fqoj t;.M,Tio22.77 Mgo 0.42;Mno 0.2i, s;o2 0.53,sio2 31.60,Beo2.65, N2o32.64.L'a\6cnryartese presente en cristati. ioin, allong6s poecilobl*tiqo"s. Elle possddeune rayure vert fonc6, une fracturein6gale, deux bons clivages'et un 6clat sub-adam*tio oon"t -6t lique. C'ist un min6ral non magn6tique,non fluorescent,qui ne r6agitpas avecla plupart des acideset basescommuns. Toutefois, elle se dissoutlentement dans I'acide fluorhydrique froid. Sa densit6mesur6e est 3.85, et sa densit6calcul6e, 3.98. Elle est opaquei sub-transparente,biaxe n6gative(?) avecun 2V important,fortement pl6ochroique La-h/eglvar.T e;tllcliniUue (couleur bronze d vert), et possbdeon indi.. de r6fuction oCde 1'78, et un indice / 9: 1.83. (pseudo-monoclinique),gioupe spatial Pf, aveca 10.3L7(l),b 10.724(l),c 8.855(l) A, a 105.77(l)",p 96.21'(1)", po[synth6{qg. septraies les i nqfi 0)" , v 730.40) F, et2 =2. Tous les 6chantillonssont fortementmacl6s de fagon T: 8.048(90X010)' itus lntensel du clicir6 de diffraction (mdthodedes poudres)ld en A(D@k[)l,sont:2.5293(100)(420), i.Wg