CanadianMineralogist Vol. 19,pp. 337-340 (1981)

SPERTINIITE,Gu(OH)2, A NEW MINERAL FROM THE JEFFREY M|NE, OUEBEG

J.D. GRICE NationalMuseunt ol Natural Sciences,Minerul SciencesDit'ision, Ottav'a, Ontario KIA 0M8

E. GASPARRINI Minntet ScientificLinrited, P.O. Box 921, Toronto,Ontario M4P 2H2

Asstnlcr Mots-c'lds;spertiniite, espbce min6rale nouvelle, hy- droxydecuprique, mine Jeffrey. Ou6bec.rodin- Spertiniite, a new speciesfrom the Jeffrev mine. eite. Quebec, occurs as small botrvoidal aggreg0tesas- sociated with chalcocite, native copper and ataca- mite on a rodingite dyke. It forms blue to blue- INtRoouc].tol.t ereen, lathlike crystals ( l0 pm in size. It is op- tically anisotropic. with parallel extinction and During a study of the minerals from the positive elongation; pleochroism is strong, with X Jeffrey mine, Asbestos,Shipton Township, Rich- colorless and Z dark blue; indices of refraction c mond County, Quebec(Grice & Williams 1979), 1.720(2), ? > 1.800(2). An electron-microprobe a natural occurrence of Cu(OH)r was dis- analysis gave 66.9VoCu and O.lVo Cl. By analogy covered.This specimenwas submittedfor identi- with (PDF syntheticCu(OH)o 13-420), spertiniite fication to one of the authors (J.D.G.) by Mr. is orthorhombic, space group Ctncm, and Z = 4; F. Spertini, Chief Geologistat the Jeffrey refined cell parametersarel. a 2.951(l'), b 10.592(3), mine, c 5.257Q\ A. fne srongest nine lines of the X-ray Johns-ManvilleCanada Incorporated; it is with powder-diffraction pattern are 5.28(80)(020). great pleasure that we name this new mineral 3.73 (e0) (02'.t\, 2.632(I 00) (002), 2.494(60) ( | 11) . speciesspertiniite. 2.362(sO)(041,022), 2.264(7OJir30), 1.929(30) The name and the mineral have been ap- (ll2), 1.716(70)( 150.132) and 1.438(30)(152) A. provedb), the Commissionon New Minerals and The nreasureddensity is 3.93(2) g/cme and the Mineral Names, I.M.A. The holotype specimen calculated density, g,/cm'. 3.94 of spertiniite consistsof a few mg of material Keyworcls; spertiniite, new mineral. cupric hv- on matrix measuring3x3x2 cm. This specimen droxide. Jeffrey mine. Qu6bec. rodingite. is preservedat the National Museum of Natural Sciences,Ottawa (NMNS 44696) along with Sovuernr cotype material (NMN^! 44697, 44698 and 44699). La spertiniite. espBcenouvelle trouvde ir la mine Jeffrey (Qu6bec), se pr6sente en petits asr6- gats botryoidaux avec chalcocite. cuivre natif et OccunnrNce atacamite associ6s,dans un dyke de rodineite. Les cristaux en lattes, de taille infErieure ir l0 um. Spertiniite is a very rare mineral, found in passent du bleu au bleu-vert. Optiquement ils sont a rodingite dyke exposedin the east side of the anisotropes,ii extinction paralldle. allongement po- Jeffrey mine open pit. At the time of discovery, sitif et fort pl6ochroisme (X incolore. Z bleu fon- January 1978, the exp.osureof the dyke meas- c6); leurs indices de r6fraction sont o l.7ZO(2), t ured I m in thicknessby 8 m in length (F. 1.800(2). IJne > analyse i la microsonde 6lectro- Spertini, pers. comm. 1980). Spertiniite occurs nique donne 66.9Vo Ct et 0.1Vo Cl. Par analogie in the lower portion of dyke near the con- avec le Cu(OH), synth6tique (PDF 13-420), la the spertiniite est orthorhombique, groupe spatial Cmcm, tact with the host serpentinizeddunite. This t 2.951(r), h r0.s9z(3), c 5.257(3) A. Z - 4. Les portion of the rodingite consists primarily of neuf raies les plus intenses du clich6 de poudre fine grained,dense, white diopsideand grossular, ld1,y1en A. (t) (/r&/)l sont: 5.28(80)(020), 3.73196; partly coated with pale green vesuvianite.Wares (021). 2.632(100)(002\, 2.494(60)(rrr). 2.362 & Martin ( 1980) gave further details of the ( (04r.022). (130\. i3'0) s0) 2.264(70) 1.929 ( rr2 t, petrology of this assemblage. 1.716(70)( 150,132) et 1.438(30)(l52). La densit6 Chalcocite commonly constitutes the core of mesurdeest de 3.93(2), calcul6e3.94. the botryoidal massesof spertiniite,which also (Traduit par la R6daction) contain atagamite. Minor amounts of copper 337

Downloaded from http://pubs.geoscienceworld.org/canmin/article-pdf/19/2/337/4005556/337_19_2_cm.pdf by guest on 27 September 2021 338 THE CANADIAN MINERALOGIST (Fig. are associatedwith spertiniite in the rodingite. gaies approximately 100 g,m in diameter A second occurrence of spertiniite from Ely' I ). SEM observation shows them to be com- a Nevada, has been reported by Miss E.E. Fejer posed of lathJike crystals, often having (pers. comm., 1980), British Museum (Natural radial habit (Fig. 2), with their longest dimen- blue to History), London ( 8M1972,193). sion approximately l0 pm' Spertiniite is blue-greenand transparent with a vitreous lustre' crusheseasily without any marked PHYSICAL aNu OPrtcll- PRoPERTIES It is soft and cleavage. It does not fluoresce in ultraviolet Spertiniite forms discrete botryoidal aggre- radiation. There was insufficient material for

Frc. l. Botryoidal aggregates of spertiniite on rodingite mafix' SEM image; width of field of view is 380 pm.

FIc, 2, Radial aggregatesof lath-like crystals of spertiniite. SEM image; width of field of view is 230 pm.

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lIM I. FRAY }CIIIRDITFMCTICtrI DAN TOR SPRTI,UTE AID SYNMMC sohrbility measurementson spertiniite, but Weast @ruc mrcro (1977) reported that synthetic Cu(OH)r is in-

soluble in cold water, decomposesin hot water PERTINITB qPuc ]mr

and is soluble in acids. .l€t fuas dcalc l@s dmeas Three grains were used in the density deter- mination of spertiniite. Grains were suspended 80 5.29 5.29 020 90 5.30 3.73 3.73 02L L00 3.73 in Clerici solution (thallous malonate/formate- 1.800(2); 1.373 L.372 22L L.372 this phasereacts with immersion 1.346 170 L.346 liquids having I.324 080 !,324 r) 1.800. 1.3L4 004 4 1.3L4 <10 1.301- 1.304 171 1,304 I r.289 240 diopside matrix, best instrument for the study of hydrous min- showed that the mineral is very fine grained, erals (neither O nor H is detected), it was in lV20 pm in size, and intimately associated our case the only one capable of analyzing with atacamite,from which it is not distinguished grains as fine as those of spertiniite. optically in polished section. The qualitative The qualitative study was done by energy- study also showed that the mineral consists of dispersion spectrometry and involved the col- copper with very minor chlorine and no other lection of X-ray spectra showing peaks at the minor elements. Quantitative analyses of the energy positions of the various elements above spertiniite and atacamite for copper and chlorine atomic number 10 constituting the analyzed gave amounts of the two elementsvery close to grains. The quantitative analyses were done by the stoichiometric values. Subsequent to this

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MN2. ]::lmE(reWMSGS]:mMNA:IroEN AcKNowLEDGEMENTS mn:mm@Mffio6 The authors are grateful to several staff members of the National Museums of Canada: Mr. J. Van Velthuizen for preparing the X-ray tu 66.9 65.1 63.1 59.5 cl 0.1 - 14.6 L6.6 powder-diffraction patterns, Messrs. I. Wain- oH id 34.9 d 23.9 wright and G. Young for the SEM photographs R. Waller for the pH r. sFeinii@ 3. Al:ffib und initial EDA, and Mr. 2. lbeLi@l @@€iri@ 4. Mti€L cf@ositu Dr. J'E. Dutrizac, of fr(cm), of affilG measurements. We thank d: rcr det@id CANMET, for providing Eh measurements' Mr. J.M. Kukielka was particularly skilUul at mounting and polishing single grains of sperti- studynone grain, about 50 g,m in size and with nite for electron-microprobe analysis. an X-ray pattern very similar to that of syn- thetic Cu(OH)2, was mounted, polished and ReEnnnNcEs anallzed quantitatively.The averageanalysis, i.e., values obtained for this grain and for the Gannl,Ls, R.M. (1954): Mineral speciesas func- the potentials, grains in the diopside matrix, is shown in Table tions of pH and oxidation-reduction to the zone of oxidation with the analysis of the associated with special reference 2, together enrichment of sulphide ore of and secondary .de- atacamite and the theoretical compositions posits. Geoc&int. Cosmochinr, Acta 5' 153-168' the two minerals. GnrcE..J.D. & WIt-lteus, R. (1979): The Jeffrey Asbestos, Mineral. Record 10, GeNrsts mine, Qu6bec. 69-80. In the Jeffrey specimens, it appears that J,rccr. H. & Oswero, H.R. (1961): Die Kristall- spertiniite is a product of the supergenealtera- struktur des Kuferhydroxids, Cu(O}I)2. Acta tion of chalcocite. Three groundwater samples Cryrt. L4' 1041-1045. the spertiniite were collected in the area where RucrclDcE, J.C. & GesrenmNl, E. (1969): EM- was found. This percolating water was found Specifications of a computer pro- - PADR VIl. to be oxidizing, Eh + O.83, which is to be gram for processing electron microprobe anal- expected for groundwater, but it was quite al- ytical data. Dep. Geol. Univ. Toronto. kaline, pH=9.2. These rather unique conditions WenEs, R.P. & MARTIN,R.F. ( 1980): Rodingitiza- sulfates,which preclude the formation of copper tion of granite and serpentinite in the Jeffrey are the normal alteration products of chalco- mine. Asbestos,Quebec' Catt. Mineral. 18, 231- cite. In this range of Eh and pH, the solubility 240. is due almost entirely to the cupric ion, and R.C. (1977): Handbook ol Chemistry and the stablesolid phaseis cupric hydroxide (Gar- Wusr. Physics (57th ed.). Chemical Rubber Publ. Co.' rels 1954). Cleveland. Ohio. From the chemicalanalysis it is apparentthat the spertiniite structure does not accept much chlorine. Any chloride ions available in the groundwater have been essential to the forma- Received October 1980, revlsed manuscript accepted tion of atacamite. December 1980.

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