Catndian Mineralogist Vol. 16, pp. 665-669 (1978)

LAUTITEAND CADMIUM.RICHSPHALERITE FROM THE ROS$ MINE, HISLOPTOWNSHIP, ONTARIO

T. T. CHEN1 euo J.E. DUTRIZAC'? M ineralo gyr and. M etallurgical Chemistryz Sections, Sciences Laboratories, CANMET, Department ol Energy, Mines and Resources,Ottawa, Ontario KIA OGI

ABsrRAcr Lautite had not been reported previously from Canada. This mineral, associatedwith a Lautite were and cddmium-rich sphalerite identi- cadmium-rich sphalerite, was recently identified fied in a single ore vein from the Ross mine, Hislop Township, Ontario; Hislop Township, Ontario; this is the first reported at the Ross mine, Canadian occurrence of lautite. Lautite, (Cu,Ag)q."" this report summarizes studies on these two As1.66S6.s6,occurs as irregular or needleJike crystals . in . Cadmium-rich sphalerite occurs as ir- regular zones bounded by galena and calcite; the Servrpr,nDescRrPtrorl highest cadmium content detected by microprobe analysis is 9.0 wt Vo. The Ross mine, about 18 km southeast of Matheson and 1 km north of Holtyre, Hislop Sorvrrraarnr Township, Ontario, is situated in steeply folded Keewatin lavas and Timiskaming sediments in- Nous avons identifi6 de la lautite et une sphal6- truded by stocks of syenite and granite. The rite riche en cadmium dans un seul filon de minerai general geology and mineralogy of this deposit de la mine Ross, canton de Hislop, Ontario. Cest have been described by Prest (1956) and Jones la premidre fois qu'on signale de la lautite au (L944). galena and sphalerite ocaur Canada.On fouve la lautite, (Cu,Ag)o.e?Asr.oo$.nr, Although galena en cristaux difformes ou aciculaires inclus dans la throughout the mine, lautite-bearing was galdne.La sphal6ritecarlmifdre se pr6senteen zones found only in the upper workings of the No. 12 irr6gulidres bord€es de galdne et de calcite. Les vein; galena from eight other active stopes was analysesi la microsondeindiquent une teneur maxr- investigated but found to be lautite-free. The mum de cadmium dans la sphal€rite de 9 pour cent cadmium-rich sphalerite seemsto be associated (en poids). only with the lautite-bearing galena. The sample (Traduit par la R6daction) investigated consists of several irregular crustifi- cations of silicates (innermost), calcite, sphale- INtnopucrtoN rite and a major galena mass. The zones are generally 1-3 mm thick, whereas the galena is (CuAsS) Lautite was originally describedfrom at least lO mm across and contains numerous , near Marienberg , where it occurs triangular pits, cleavagesand fractures in curved , with native arsenig, , chalco- alignment suggestive of a deformation fabris. pyrite, galena and barite @alache et al. 1944). , nickeline, silicates, calcite and other The mineral has been found in only a few tetrahedritrtennantite occur as inclusions in the localities, e.9., the Gabe Gottes mine, Alsace- galena; chalcopyrite, pyrite, marcasite, gypsum, (Marumo Lorraine, France & Nowacki 1964), nickeline. ram,melsbergite and electrum are in- (Hiigi Is6rables,Wallis, Switzerland et aI. 1967) cluded in the silicate zone. Gypsum fills inter- and the Hechtsberg Qurry, Kinzigtal, sticesbetween galena, sphaleriteand calcite. The (Otto 1974). association of nickel arsenides with lautite- Cadmium is a common trace constituent in bearing galena seems to be characteristic and sphalerite.Although synthetic CdS forms a com- could serve as a guide to this rare mineral at tle plete solid-solution series with ZnS at high Ross mine. te.mperature (Charbonnier & Murat 1974), naturally occurring sphaledte with more than Rnsurts eNp DrscussroN 1.0 wt. Vo Cd is rare and has been noted in only a few deposits,e.g., Bernic Lake, Manitoba Lautite (Cd 17.6 wt. Vo; Cernf & Harris 1978) and Pay Khoy, northern Urals, U.S.S.R. (Cd. 2.5 Lautite is found as small (20_l4O p,m) wt. Vo; Yushkin et al. t975). irregular to needle-likecrystals in galena(Fig. 1)' 665 666 THE CANADIAN I\{INERALOGIST

lautite matrix. In general, however, the analyses indicate a composition of CuAsS with little de- parture from stoichiometry, in agreement with the study of Maske & Skinner (1971). The highsl silver contents of lautite from the Ross mins in{isa1s that (Cu",A.g) substitutions can be relatively important in lautite from silver-rich environments. The minor substitution of Sb for As is consistent witl the phase studies of Luce et al. (1977). X-ray diffraction study of Ross mine lautite was difficult because of its small grain-size. The Gandolfi patterns obtained with a 57.3 mm diameter camera inevitably showed galena lines and a few weak lautite lines: 3.10(m), 2.98(m, overlapsgalena), 2.06(w), 1.90(m), 7.74(n, Frc. l: Needle-like lautite (dark erey) in galena (light grey); oil immersion. overlaps galena, 1.64(w) and 1.61(w). Com- parison of these lines with the data for lautite from the type locality (Table 2) togpther with The mineral is light grey with moderate bire- the optical and microprobe analysesconfirms the flectance from pink or brown to blue, and occurrence of tlis mineral in the Ross mine. with distinct anisotropism from bluish grey to The cell dimensions calculated for tle Ross mine light greyish browu in oil. The optical properties lautite, assuming the space group Pna2t, are a are simil2l to those of enargite. L1,4, b 5.5 and c 3.74, in close agreementwith As can be seen from Table 1, the composi- the values given in Table 2 and by Craig & tion of lautite from the Ross mine is fairly Stephenson(1965). uniform; in addition to major Cu, As and S, Some confusion surrounds the powder-diffrac- minor amounts of Ag and Sb substitute for Cu tion data available for natural and synthetic and As, respectively. Hg, Fe, Zn and. Bi were lautite. The orieinal data listed in JCPDS 12155 not detected. The average electron microprobe were indexed according to Y2t2t2i this sp.se analysis corresponds to (Cu,Ag)o.sr(As,Sb)r.oo group is now known to be incorrect (Craig & So.ss.A lautite specimen from Lauta, Marien- Stephensen1965, Marumo & Nowacki 1964). A berg, Saxony (National Mineral Collection No. calculated pattern (25-1179) has been given in 14870) was found to have an averagecomposi- the JCPDS file for natural lautite, but the tion corresponding to Cur.orAst.ooSo.gs(Table 1). calculated intensities often differ significantly The slightly low total for lautite from the Ross from the measured values. Maske & Skinner mine is probably due to the small size of the (1971) correctly identified the lautite space lautite grains; the departure in molar ratios fTom group as Pna2\ but to provide a consistent basis the ideal 1:1:1 is possibly caused by the use of comparison with JCPDS 12155, they in- of standards that do not exactly duplicate the dexed their data for synthetic lautite using the TABLEI. ELEC1RONMICROPROBE AMLYSES OF LAUTI'IE

l,leiqht percent RossMine,0ntario Lauta, lilarienberg, Saxony

I Av. As 44.3 42.7 4s.0 44.3 43.8 43.6 44.2 M.0 44.2 M.2 44.4 44.6 M.6 44.4 '18.2 s I8.2 r8.4 18.7 r8.6 18.6 t8.8 19.1 18.6 18.3 18.2 18.1 17.9 l8.l Cu t7 I 37.2 34.7 35.t 36.3 35.9 35.2 35.9 38.3 38.0 38.3 37.7 38.1 38.1 .n.d. Ag n.d. 0.2 1.0 1.0 0.1 0.6 0.4 0.5 n.d. n.d. n.d. n.d. n.d. sb o.2 0.6 0.4 0.3 0.6 0.2 0.1 0.3 0.t 0.t 0.1 0.1 0.1 0.1 '100.8 Ioral 99.8 99.1 99.8 99.3 99.4 99.t 99.0 99.3 100.610t.0 100.5100.7 100.7

Atomic ratios

(As,Sb)r.00 t.00 1.00 l.oo i.o0 l.0o t.00 1.00 1.00 r .00 1.00 r .00 I .00 1.00 s 0.96 1.00 0.97 0.98 0.98 l.0l l.0l 0.98 0.96 0.96 0.96 0.95 0.94 0.95 (cu,Ag)0.99 1.02 0.92 0.95 0.97 0.98 0.94 0.97 1.02 0.01 1,02 1.00 l.0l I .01

Analytical conditlonsi standards: enarglte (Curo,Astrq,S](o),argentopyrite (Aqrq) and chalcostibite (sbra)i EMPADRVII correciion program(Rucklidge d easiirrtni'li69ii 2okv. LAUTITE AND Cd-RICH SPHALERITE 667

TABLE2. X.RAY POWDERDIFFRACTION DATA OF LAUTITE FROMLAUTAT MARIENBERG, SAXONY

dcalc dneas rest dmeas /est l,kl hkl dcalc

200 5.678 5.70 3 221 2.055 2.057 4 110 4.9144.90 1 420 I .966 1.966 112 201 3.1291 321 1.905 1.904 B t 3103.109 I 3.r45 loB 600 1.8931.891 6 01r 3.0s0I 002 1.875 1.875 2 'll I 2.981 2.977 3 sil 1.830 1.83r ? 400 2.839 2.836 2 130 1.7941.796 2 211 2.714 2.715 3 szl r.7asfr.7a3 4 120 2.650 ?.647 1/2 42't r .74rI Frc. 2: Cadmium-rich sphalerites showing crude (light grey); 410 2.5182.515 2 230 1.730 1.730 I hexagonal or striplike "patches" etched witl 1:1 HNOg; oil immersion. ?20 2.457 2.459 3 601 1.690 1.688 a. 3ll 2.393 2.395 I r.638f 330 r.636 4 The Iines were indexed assuming the space 320 2.212 ?.212 1 03'l 1.635 group Pna2t (Craig & Stephenson 1965); the '13'l ) 121 2.164 2.155 3 r.6tBfr.ot6 calculated cell parameters are a 1I.355 (5), , 510 2.096 2.096 1 6lt 1.6r41 5.450(2'), c 3.75O(2)4. The d values and in- tensities correspond closely to those of natural 4ll 2.0902.091 2 312 I.606 I.606 lautite (JCPDS 12-755); it is not known why the calculated intensities (25-1L79) are somewhat 114.6ilmDebye-Scherrer camera ; Coro radiation different. There is relatively poor agreement in (L= t.zgozi); d valuescorected with si standard d values < 1374 between the data for natural .l.I.355, (a=5.43088fi). Indexed with a= b= 5.450, lautite and for the synthetic phase of Maske & (L971); e= 3.750i,assumed space group rhazl. Skinner the reasons for this are not obvious, as the two phases are similar in com- F2t2t2t space group. Furthermore, there are position. some slight but potentially significant differences Cadmium-rich sphalerite in d values less than 1.97A between natural (JCPDS L2155) and synthetic lautite. For Although sphalerite occurs throughout the these reasons it was considered worthwhile to Ross mine, most of this is "normal" with respect redetermine the X-ray powder-diffraction pat- to cadmium concentration: Zn 66.6, Cd 0.4" Fe tern for lautite from the type locality. The 0.1, S 32.8 (wt.%) Cadmium-rich sphalerite results of this investigation are given in Table 2. (Cd > I wt.Vo) seemsto be associatedonly with TABLE3. ELECTRONMICROPROBE AMIYSES OF CADI41UM-RICHSPHALERITi FROM IIIE ROSSMINE

lleight percent 1 2 3 4 5 6 7 I 9 10 ll 12 Fe 4.3 6.9 5.9 2.8 2.9 ll.5 2.7 1.9 10.3 5.1 13.7 5.9 ',l cd 6.9 5.8 5.8 7.0 7.6 5.6 6.7 6.1 9.0 6.2 4.7 .8 Zn 55.2 55.8 56.3 57.6 57.1 50.3 57.8 59.2 50.4 56.3 48.7 59.6 s 32.7 32.3 32.5 32.3 32,5 32.5 32.5 32.3 3l.6 32.3 32.4 32.7 Total 99.1 100.8100.5 99.7 100.1 99.9 99.7 99.5 101.3 99.9 99.5100.0

Atomicratios (Fe+ Cd+ Zn = 1.00) Fe 0.08 0.1? 0.10 0.05 0.05 0.20 0.05 0.03 0.l8 0.09 0.24 0.I0 cd 0.06 0.05 0.05 0.06 0.07 0.05 0.06 0.06 0.08 0.06 0.04 0.02 Zn 0.86 0.83 0.85 0.89 0.88 0.75 0.89 0.91 0.74 0.85 0.72 0.88 'I s .04 0.98 I.00 I .0t t.02 I.00 | .02 I.01 0.95 1.00 0.98 0.99

Mn' In andHg are less than 0.08 wt.%. Analytical conditlons: 20kV;synthetjc standards:(Zn,Fe)S with 4.75 wt.% Fe for Zn{(!, Fe{o and SXdlines, CdSfor CdId line: EMPADRVII corection program. 668 TI{E CANADIAN MINERALOGIST

5 to t5

,::f -

tattt a ""-"$ t a oo-r?^! . t' o$oq . ttll.tt . - i.t o.F.-f,-b ;ii-.i'S:u'ii'. ' ZnS 95 90 85 80 75 70 .-ZnS Fro. 3: Molar compositions of sphalerite samples from the Ross mine. "Normal" sphalerite from this mine is shown by the dashed line and "8 veins". The solid points are for cadmium-rich sphalerite associated with lautite-bearing galena. The open circles are the values for tle "patches" and the crosses are the corresponding matrix compositions. the lautite-bearing galena. This sphalerite concentration commonly increases as the iron generally occurs as a slightly concavezone, with increases. the outer part separatedby the galena and the In one section the "patches" were sufficiently inner part bounded by euhedral calcite. The coarse to permit their analysis with minimal sphalerite contains numerous minute inclusions interference from the matrix sphalerite. De- of chalcopyrite, gilena, pyrite, silicates and pits tailed analytical data are presented in Table 3 that increase in abundance towards galena. for both the "patches" (6 and 11) and the 'opatches" Numerous chalcopyrite and marcasite veinlets matrix (12). The are clearly cad- and cracks are present, and the cracks are mium-rich with respect to the surrounding roughly perpendicular to the concave outline. In matrix sphalerite, and have the compositional polished thin section under transmitted light ranges(wt.Vo): Zn 48.7-51.3, Cd 3.8-5.6, Fe some of the sphalerite also shows color banding lL.5-L4.7, S 31.6-32.9; their average composi- from yellow to reddish-yellow to dark brown. tion is (Zno.z"Cdo.oaFeo.ss)$.seowhereas that of The inner bands adjacent to calcite are yellow the matrix is (Zno.eCdo.orFeo.to)So.rn. and free of inclusions whereas the outer bands The X-ray powder diffraction pattern (Gan- are dark brown with abundant inclusions. The dolfi camera) of a crystal consisting mainly of 'opatches" sphalerite contains many light-colored "patches" is similar to tlat of synthetic sphale- which also proved to be cadmium-rich. The rite (JCPDS 5-566). The cell parameter cal- 'opatches" and the matrix sphalerite are optically culatedis 5.421(1)A. similar but are readily resolved after etching 'opatches" with 1:1 HNOg. The are irregular, AcntownocnMENTs mostly stripJike masses5-75 g,m lone (Fig. 2) that seemto radiate towards the concave outline; The authors thank E.W. Johnson of Pamour a few of them have crude hexagonal shapes. Porcupine Mines Limited and P. Baleck of the The cadmium-rich sphalerite was subjectedto Ross mine for supplying specimens from the microprobe analysis. Some of the results are Ross mine and H.R. Steacy of the Geological summarized in Table 3; all of the analytical Survey of Canada for contributing the lautite data are displayed graphically in Figure 3. In specimen from Lauta, Saxony. The technical 'onormal" contrast to the sphalerite in the Ross assistance of E.J. Murray, D.R Owens and mine (Fig. 3), the cadmium-rich sphalerite is J.H.G. Laflamme is also recognized. variable in composition over the following ranges (wt.Vo): Zn 48.2-66.1, Cd 0.4-9.0, Fe RsnnnnNces 1.0-15.8,S 3 1.6-33.9 (total 99.1-l 0I.3 Vo) . The highest cadmium concentration observed was dnmri, P. & Hennrg D.c. (197S)The Tanco peg- 9.0 wt. Vo. From Figure 3 it is hard to draw matite at Bernic Lake, Manitoba, K. Native any conclusion about the effect of iron on the elements, alloys, sulfides and sulfosalts. Can. degreeof cadmium substitution, although the Cd Mineral, L6, 625-640, LAUTITE AND Cd-RICH SPHALERITE 669

CnenroNNrnn, M. & Munel M. (L974): Sur la Mlsrr, S. & SrrNNs& B.J. (1971): Studies of the d6termination des diagrammes de phases i tem- sulfosalts of copper. I. Phasesand phase relations p6rature ambiante des sulfures mixtes appartenant in the systemCu-As-S. Econ. Geol.66, 901-918. aux systbmes Zn-Cd-S, Zn-Hg-S, Cd-Hg--S. C.R. Acad. Sci. Paris, 278(C), 259-261. Orro, J. (t974) :Eine neue Kobalt-Kupfer-Arsen- Silbermineralization im Kinzigtal (Schwarzwald). Cnerc, D.C. & SterHENsoN, N.C. (1965): The Aufschluss 25, 513-524. crystal structure of lautite, CuAsS. Acta Cryst. lg,543-547. Perecxr, C., Bmuex, H. FnoNpsr-, C. (1944): The System of Mineralogy I. Elements, Sulfides, Hiicr, T., Kdnrer-, V. Dr QurnverN, F. & RrcrsN- Suffosalts, Oxides (7tb ed.) John Wiley & Sons, BAcK, E. (1967): Die Uranvererzungen bei Is6ra- New York. bles (Wallis). Beitr. Geol. Schweiz, Geotech. Ser. 42. PREsr, V.K. (1956): Geology of Hislop township. Ont. Dep. Mines Ann. Rep. 65(5), JoNrq W*A. (1944): Mineralogy of tle Ross veins, Ramore, Ontario. Can. Inst. Mining Met. Trans. RucKLrDuE,J.C. & GaspenmNr, E.L. (1969): Elec- 47, 55-70. tron microprobe analytical data reduction, EMPADR YII. Dep. Geol" Uniy. Toronto. Lucg F.D., TurrLE, C.L. & SrrNNEn, B.l. (1977): Studies of sulfosalts of copper. V. Phases and YusHxrN, N.P., YennurN, N.I. & Konosnn ove, phase relations in the system Cu-Sb-As-S be- L.A. (1975): New manganiferous variety of tween 350' and 500'C. Econ. Geol.72,27L-289. sphalerite. Dokl. Acad. Jci. U^ISR (Eartlt Sci. Sect.) 216, L66-169. Menurvro, F. & Nowncn, W. (1964): The crystal structure of lautite and of sinnerite, a new mineral from the Legenbach quarry. Schweiz. Mineral. Received laly 1978; revised manuscript accepted. Petrogr. Mitt. 44, 439454. Aaswt 1978,