Canadian Mineralogist Vol. 19, pp. 583-5910981)

THETEAGHING OF GOPPERFROM ANILITE AND THEPRODUCTION OF A METASTABLEGOPPEF SULFTDE STRUCTURE

R.J. GOBLE Department of GeologX, Ilniversity ol Nebraska-Lincoln, 433 Morrill Hall, Lincoln, Nebraska 685854340, U.S.A.

ABSTRACT INrnonuctroN Natural leaching of sulfides (Goble 19g0) The structural characteristics of the eieht results in a mineralogical change from diurleite low-temperature copper sulfide minerals ide-nt- to anilite (Cu,.rrS) !ft'.rrS) to spionkopite (Cur.*S) ified to date are listed in Table l. If allowance is to yarrowite (Cur.,rS) to covelline (CuS). Anilite made for the presenceof covalently bonded sul- specimens leached artificially in a ferric sulfate fur layers such as exist in covelline, solution show a compositional change correspond- these struc- tures can be described ing to the change from anilite to yarrowite Uut Oo to a first approximation in not develop the hexagonal yarrowite structure. terms of cubic and hexagonal close-packed ar- These leached anilite spocimens devetop a structure rays of spherical sulfur atoms, with the smaller similar to the pseudocubic structure of geerite copper atoms occupying interstitial positions. (Cur.mS). The structure of leached anilite, by anal- In the ideal cubic and hexagonal close-packed ogy with other copper sulfide structures. shows arrays, the distance D between sulfur layers is dimensional characteristics predicted for composi. equal to 2R\/2/3, where R is the radius of the tions of both Cur.rsS and Cu1."oS. The artifiiially sulfur atoms. Relatively intense reflections from leached anilite remains metastably in this structure planes with spacings corresponding both to compositions approaching covelllne. X-ray to R and D powder patterns of leached anilite stronglv re- can be identified on X-ray patterns of semble those of tbe blaubleibend covellines.-raisins the copper sulfides. The observed spacings of questions about the identification of these phasei R and D are plotted as functions of composi- by powder methods. tion in Figures lA and lB, respectively; the Keyv,ords: anilite, leaching. copper sulfides, Dlaz, ideal relatignship R : D/2\/2/3, determined bleibend covelline. from the data of Figure 18, is plotted in Fig- ure lA. Sovuarnn The copper sulfides of Table I can be sub- Dans la nature, le lessivage de sulfures de cuivre divided into three general groups basedupon the (Goble 1980) donne lieu i la transformation min6- information summarized in Figure 1A. Group I ralogique djurl6ite Cu1.e7,S-+ anilite Cu,.rog + consists of those minerals with spionkopite Cu1.a6S-+ yarrowite Clrr.,oS-+ covelline approximate CuS. Les 6chantillons d'anilite lessiv6s au labora- cubic close-packingof the sulfur atoms (geerite, toire dans une sglution de sulfate forrique mon- anilite, digenite). Group 2 contains those min- trent un changement de composition allant jusqu'i erals with less copper than Group l; these are la yarowite mais sans apparition de la structure characterized by hexagonal close-packed sulfur hexagopale de celle-ci. Ces 6chantillons tessiv6sonr layers interspersedwith covalently bonded sulfur qlutdt la stnicture pseudocubique de la geerite layers (covelline, yarrowite, spionkolite). Cu,.uoSet. par analogie aux structures d,autres sul- Group-3 minerals have more copper than the fures. de cuivre, montrent les caract6ristiques di minerals in Group 1 and are characterized by mensionnelles pr6wes pour les compositions Cur.rss approximately et Cur.s,S. L'anilite ainsi lessivde hexagonal close-packed sulfur artificiellement (, adopte. de fagon m6tastable. cette structure jusqu'i layers chalcocite). However, the dis- des compositions voisines de la covelline. I_es ili- tance between layers in Group-3 minerals is too ch6s de poudre de ces produits ressemblent forte- great for truly hexagonal close-packing. The ment d celui de la covelline blaubleibend, rendant structural stability of the sulfur layen is remark- douteuse I'identification de ces phases par cette able and permits wide compositional ranges m6thode. for many of these minerals, even though signifi- (fraduit par la Rftaction) cant parts of the ranges may be metastable Mots-clCs: anilite, lessivage. sulfures de cuiwe. relative to rearrangement of the sulfur frame- covelline blaubleibend. work. 583 584 TIIB CANADIAN MINERALOGIST

TABLEI. CO}IPOSITIOI{,CRYSTALLOCiAPHY AIID STABILITY OF IIIE EICM $Ol{ll COPPERSULFIDE I.IIIIERALS

itAtll'lull THERI.IAL . C(}||MSITION CRYSTAI. SPACE STABILITY 'ilIriEML MrE srrucruRAr 0BSERVED SYSTEI GRoUP (.C). REFEREIICES

coYelllle Cur.ooS Cu1.96S H€xagonal P63/m Berry (1954), Kullerud ( 1965), Potter (1977) yamlte Cu1.!2S Cur.o-r.zS Heegonal P5!l, Plnl 157 lbh (1964), or P32l Potte. (1977), Goble (19&) splonkoplte Cur.qoS Cut.3-l.ss Hexagoml P3:nl, P3nl 157 l.loh (1964), or P321 Potter (1977), Goble (1980) gerlte Cu1.5eS Cu1.5-1.5S (Pseudocublc) (rA'3n) ? Goble & Roblnson (r980) anlllte Cur.z5s Cur.zs-r.goS 0rthorhotrblc Pnm 70 lilorlmto et al. (1e69), f4;rl;6-to & Koto(1970) dlgenlte Cu1.g6S Cur.zl-r.goS Cublc ros lhrlmto-& Kullerud(1963), Roseboon(1966) dJurlelte Cr,.rrS c".rr-r.rrs orthorhmblc Pmtr Uorlrcto (1962), Roseboon(1966), Pottef & Evans (re76) chal@clte Cq.ooS Cu, l.lonocllnlc P\tc t03 Roseboon(1966), .rr-r.ooS Evans(1971 ), Potter (1977)

ronly lo-tspeEt!re fom are llsted tPseudony6: covelllne: covellite; yarmlte: blaubletbend covelllne I r blue-remlnlng covelllnei splonkoplte : blaublelbend corelllne 1l : blue-remlnlng covelllne

In a study* of copper sulfides from south- produce the replacement of anilite by spionkop' western Alberta, Goble ( 198O) noted that ite or yarrowite while observing the structural natural low-temperature leaching of coplrr from change on the X-ray precessioncamera. these sulfides led to the progressive replacement of djurleite by anilite, then spionkopite, yar- PRocEDURES rowite and finally, covelline. lfu'eugh6uf this replacement, the orientation of the crystallo- Natural specimens of anilite from the Yarrow graphic planes corresponding to R and D of Creek - Spionkop Creek area of southwestern Figure 1 remains constant; D is readily located Albrta were used for the leaching experiments. perlrendisular to the cleavage of all these min- Associated minerals are bornite, yarrowite, spion- erals. R and D can be observed on X-ray pre- kopite, djurleite, wittichenite and . cession photographs by choosing the hexagonal One set of anilite preces$ion and Gandolfi a and c axes as precession o(es. For this reason, films was used as a standard after comparison orientations will be referred to the hexagonal 4 with the data of Morimoto u al. (1969). For and c il(es throughout this PaPer. the leaching experiments, cleavage fragments of anilite were identified on a polished surface Coupled with the loss of copper from the using optical techniques, plucked from fie sulfides, there is a progressive change in cell polished surface, mounted on glass fibres and dimensions as shown in Figure 1 and, for the photographed using a 114.6-mmdiameter' Gan- range Cur.eoSto Cur.oo"S,a corresponding series dolfi X'ray camera. The resulting films were of structural changes from the geerite to the compared with the standard anilite film to spionkopite to the yarrowite to the coYelline confirm the optical identification. Each anilite structure (Goble 1977, in prep.). The present fragment was then transferred to a goniometer study outlines an attempt to artificially re- head and oriented using a precession calnera (Mo radiation) to arrange as precession axes those anilite axes coresponding to the hexa- gonal a and c axes of yarrowite, spionkopite (anilite 6 and respectively). &Note on p. 511, in the abstract, and on p. and covelline [101], that parallel perpendi- 513, second column, line 26 of tlat paper, the cal- These orientations arb and culated density is given as 5.13 e/cm8. This aplllies cular, respective\, to the sulfur layers and to to the natural material, Cur.uS. The calculated the cleavage in covelline, yanowite, spionkopite, density for spionkopite Cur.4S should be 5.33 and anilite. Zero-level precession films were g/cmu, prepared and compared with the standard in- THE LEACHING OF COPPER FROM ANILITE 585 dexed anilite films. For the specimensused, this 1.98 comparison revealed minor amounts of oriented (A) djurleite intergrown with the anilite. The grain, 1.96 still mounted on the goniometer head, was then immersed in an acidic ferric sulfate solution 0 for a set period of time, with experimentaf con- R= 1'ea ditions as outlined in Table 2. Upon removal 2v'ffi n tAt from this solution, the grain was washed with distilled water and photographed on the X-ray 1.92 precession camera. This process was repeated until a structural change was observed, at which time a complete set of X-ray films was pre- 1.90 pared. Upon completion of the X-ray analysis, run 3.4 products were mounted in epoxy and analyzed (B) using an Applied Research Laboratories AMX electron microprobe equipped with a Tracor a 3.2 Northern NS-880 energy-dispersion spectro- D(A) meter. Fragments of unleached anilite also were analyzed. Operating sonditions were: accelerat- D.0.655(Cu:S) 3.0 + ing voltage 15 kV, sample current about 1.5 2.069 nA, beam diameter about 2 g,m. Standards used were CuS and Cur.ss. Apparent concen- 2.8 trations were corrected for absorption, second- ' ary fluorescence and atomic number effects t.o 1.2 1.1 1.6 1.8 2'0 using a general ZAF program, TAPEEMX2 Cu:S rotio (Dep. Geol. Sci., Queen's University). Frc. l. Variation with composition: (A) of the radius R of sulfur atoms in the close-packed CHer'rrc.u- lNo Pnvstcet, CHANcES IN layers and (B) of average distance -D betw-een Leecnao ANILITB close-packed layers in the copper sulfides.- Ideal struct;ral compositions are used. The ideal rela- minor changes in the spacings of Only very tionship for close-packed structures, R .= Q/ the crystallographic planes of anilite were ob- 2\/2/i, using R from Figure lB, subdivides the served as a result of immersion in the acidic coppbr sulfides into three groups as shovn- R ferric sulfate for periods of up to ten hours, is-ihe spacine (110) of covelline, (040) of whereas immersion for twelve hours produced anilite, (b46) of djurleite, (630) of chalcogtte jarrowite, a major structural change readily observable (Potter & Evans 1976), (110) of (Goble (220) of on precession photographs. Immersion times ioOO) of spionkopite 1980), (Goble 1980) and (10-.10.0) greaier twelve hours (up to ten days) geerite & Robinson than (Donnay et al. 1958). D is the observable structural of digenite produced no additional (006) of covelline, (202) of anilite' correlate spacing No attempt was made to (ioo)-or djurleite, (204) chalcocite (Potter & "hatrger. the iate of change with concentration of the Evans 1976), (00.24) of yarrowite, (00.14) of ferric sulfate solution. Therefore, the times spionkopite (Goble 1980), (111) o! geerite listed indicate the chronology of change for only Goble & Robinson 1980) and (555) of digenite one particular set of conditions. C. Harlem and (Donnay et al. 1958). Modified from Goble L. Whiteside (pers. comm. 1981) produced a (1977).

TABLE2. COIIDITIONSFOR LEACHING EXPERIMENTS

STRUC'TUML TB.IPERAIURE-i;bl'--- Fe,(SO").'xlL0 SOIUTION SAMPLE sIzE CHANGE RuNTME pH'-"'i3i8entiatlon volme

-5 -50x100x200 none hours 25 -5 -10-3M mt um l0 -lo-3 -5 -50x1OOx2OO conplete 12 hou6r 25 -5 ilr ml um -10-3 M -5 ml -50x100x200!m conplete '107 days 25 -5 -100xa]0x2@ complete days ,6 -5 -10-3 M mI !m

*HARLEI (p-ers.com. l98l) produceda structural changeln l2 houls at F92(S0r)3'xH20 & LIHITTSIDE perlod 3 - 5 ninutes' ;;;;;1;"ii;;;i-lri'5'ui ttrechinse'ih structure occurred over d of 586 THE CANADIAN MINERALOGIST

ANIUIE . ' aaaaa

. . 0010r .

aa a . .O b^- . t'" I .5 t- =ov roY aa

f o OR

.! I f,ml'

ftl

ol .l

ng' 2'pbservgd precession qnilits; d{a for (A) perpendicular to the (r0l) cleavage and to the sul- fur clgse-packed layers..in the structure ana' (il)'pirallel to G frorl cleavage and to the sultur close-packed rhe layers in structure. The reciprocaf httice of covelline-in the Jquivalent orientations is reproduced on a smaller scale on the lower teft of both figures. The positions of the reciprocal axes of anilite and covelline are indicated, as are the D and R ieflections of rigure t.

O040on . 'olg.' . .. ' ' a1120cov ttn f . xon -6"'.. ' . . I '.. )4oi. . 4"*{o"' iB"':'.:' ..OR

:.d I L-f I t ?! :

F Observed precession 9 l' data for anilite leached in acidic ferric sulfate solution for twelve Orientations hours. are the same as in (A) Figure 2A and (B) Fieure- 2B. structural change after twelve hours in a similar The reciprocal lattice of anilite a$ seen on experiment; the complete change took place over precession photographs (precession axes a period of 3 to 5 minutes. che*Borarr4r,eagoaar) is reproduced in Figurer 2A THE LEACHTNG OF COPPER FROM ANILITE and 28. The reciprocal lattice of the leached reflections and an addition of some reflections product after immersion in acidic ferric sulfate of leached anilite; the spacings of the remaining solution for twelve hours, using the same orien- anilite reflections have changed. The reciprocal tations, is shown'in Figures 3A and 38. For lattice of leached anilits 6s.t not, however, re- comparison purposes, the reciprocal lattice of semble the reciprocal lattice of covelline or the the hexagonal sulfide covelline in the equivalent similar' reciprocal lattices of yarrowite and positions is shown on a smaller scale in the spionkopite, as was expected from the observed lower left corner of both figures. The reciprocal replacement sequence in natural specimens. It lattices of yarrowite and spionkopite are similar does strongly resemble a geerite (and ) to that of covelline (Goble 1980). reciprocal lattice in this orientation; the reci- (Jsing ch"ogo*r €N n pr€c€ssion axis, the reci- procal lattices of leached anilite and geerite are procal lattices of anilite (Fig. 2A) and leached ihown at the same scale in Figure 4. One anitite (Fig. 3A) are very similar. However, striking difference between the reciprocal lat' the spacing of the R plane (ll0 covelline, 04O tices of leached anilite and geerite in this orien- anilite) decreasesfrom 1.958 to 1.9O2 A, the tation is the doubling of some reflections on spacings of other planes decrease by a corre- the former, the most important doublet being sponding amount, and the diffraction symmetry two reflections corresponding to the D spacing changes from twofold to sixfold. The reciprocal ( I l1 eeerite, -2O2 anihte). The spacings for lattice of leached anilite is virtually identical this Ooubletare 3.lt A (D') and2.82 A (Dr) to that of covelline in this orientation. as compared with 3.128 A for geerite. LJsing dr.ogooao{l & precession axis, the reci- Gandolfi simulated powder patterns were pre- procal lattices of anilite (Fig. 2B) and leached pared for the leached anilite; lines on the pat- anilite (Fig. 3B) are again somevihat similar, terns are diffuse and difficult to measure ac- but there has been a loss of numerous anilite curately, similar to reflections commonly ob-

Frc. 4. Observed precession data for geerite (right) and leaqhed anilite (left) in the same orientations as in Figures 28 and 3B. 588 THE CANADIAN MINERALOGIST

..- --TABLE3. X-MY POWDERDATA FOR LEACHED ANILITE ANDSELEcTED MTURAL AND syNrHnic ar_eDglFis-Enii' ;6uEilrNrs

LEACHEDANILITE natural(ya*owll"T*tttt*:,'3}:!h:ii" syntheric re65dess (A),.0,(n:il:'rii'o)n,.,,"I|',1:#',iiril,,l;fjir,lili,

25 3.273 <5 3.293 100 l0 3.108 3,28 100 3.215 104 20 3.22 l0l vl, 3.24 50 3.04'l 3.061 ai I08 tuz s 3.07 I5 2,U4 20 2.796 00.24 20 2,730 40 2.6 | 103 m/s 2.85 2.767 10.l3 ?n 2,75 006 m 2.73 I 2,075 (r0.25) 2.09 106 'l 2.06 008 100 .888 100 1.899 1l0 lnn I.896 107 vs 'I1.896

All_reflectlons on the'leached-anlllte powderphotograph are very dlffuse. covelltne,1;iiii:fi't.3i ;ffi.1:li t.,Brr:,Hl,ltirtsri!:iii.ti;ri, :lir*;,j;:irl.". andl.eoz A ror irre-rerii;ii;;;;;i;;i;i"to (rro) of covelrne.

TABLE-4., ELECTRON-I4ICROPROBEAMLYSES OF AI{IL ITE ANDANrLrrE LEAcHED rNeclorc Fennic-iu'lFeii'-

TlmeLeached %Cu ZS ,% Cu:S Comnents

unleached 't0l An 79.52 22.06 .58 r.82 unleachedAn 80.37 32%Dl, 68%An 22.04 102.4r 1.84 41%DJ, 59%An '1.08 12 hours 69.33 32.37 l0l .70 12 hours 69.04 29,91 98.95 12 hours 64.2 29.9 98.I averase= t.l5 12 hours l:13 ot.l 28.1 95.I 1.20 7 days 67.31 31.58 98.89 1.08 7 days 69.4 Jl.v 10t.3 7 days ov.v 31.8 t0l .7 averase. r.ro 7 days l:l? 69.8 3I .5 l0l.2 t.'t2 i0 days 68.43 32.58 l0r.0i I.06 l0 days 67.22 33.36 100.58 l0 dpys 70.l5 34.79 104.94 averase- t.o4 I0 dirys i.33 70.80 33.l4 | 03.94 1.08

Percentagesof anirite (An) and-dJurreite (DJ) are calcuratedbased upon idea.l sion^rii,i-iugs".i'ir,ii'i,ijir,"l"!i'q:;l,llf.'il.l;t;"li'Bi!llfflr,rl;ei"f*S:;stoi chiornetric compositioni arecus and Cu,.uS for cuand s. zAFio".e.iio,il iiiii"a. served in the blaubleibend covellines. Table 3 grains leached in ferric sulfate solutions for Iists the powder data for leached a"ruie tO periods of twelve hours, seven days and ten shows comparable data for btaubleibuni **l_ days are shown in Table 4. The starting material gegenEd by !^ng earlier workers (frenzet shows an excess of copper compared-with 1959, Rickard, 1972, that Goble l98O). fh"'powE, present in stoichiometric aniti0e (Culr$). pattern of leached Faint anilite is very similai to the djurleite reflections are present on patlgrn.of- yarrowite (Goble the'preces- lg'90) and is vir- sio:r photographs; this intergrown djurleiti tually- indistinguishable prob- from the' blaubteibeid ably accounts for some of the eicess. covelline patterns presented Micro- by Rickard (lg7}) probe analyses of the associated and Frenzel (1959). djurleite show traces of iron (up to O.4Vo) and silver. No Results of microprobe analyses - of some of components other than copper and sulfur were the anilite used in tle experiment and of anilite detected in the anitils ftagrn6nts used. After THE LEACHING OF COPPER FROM ANILITE 589 immersion in acidic ferric sulfate for twelve hours, the anilite composition changed from Cur.*1o.orSto Cur.tso.oaS,after seven days to Cur.rolo.of and after ten days to Cur.or+o.ogS.No evidence of compositional zoning was noted on X-ray patterns or in microprobe analyses, nor 3.1- was there evidence of detectable quantities of 'ideaf' D(A) iron entering the structure. The com- microprobe position of leached anilite can be determined 2.9 using the spacings of those planes corresponding to D and R and tle structural-compositional relationships of Figures 5A and 59, respectively. '1.6 Precession photographs were used to determine 12 1.1 1.8 the spacings because the reflections were sharper Cu:S rqtio than on the Gandolfi photographs. The R re- flection has a spacine of. 1.902 A, correspond- ing to an "ideaf' composition of Cur.r"S: the D reflection is a doublet with spacingsof 3.11 and 2.82 A, corresponding to "ideal" compositions a/ .96 of Cur.ooSand Cur.rsS,respectively. (a The specimens of leached anilite used in the microprobe analyses were examined using the .91 reflected-light microscope. In air the material R(A) is bireflectant in blue and bluish white; in oil .92 these colors are sligfttly darker, and the blue takes on a violet tint similar to that observed in yarrowite. Under crossed nicols the leached material is strongly anisotropic in orange. The extinction positions are oblique to the anilite cleavage, in contrast to natural blaubleibend 1.0 covellines, which show extinction positions paral- Cu:Srotio lel and perpendicular to this cleavage when in replacement of anilite. Frc. 5. Variation with composition: (A) of drstance D and (B) of radius R for tle copper sulfides. DrscussroN The spacings of the D doublet and of the & reflection of leached anilite are shown with tle The material produced by leaching anilite in compositions determined for the structure from range deter- acidic ferric sulfate solution has a structure these spacings. The compositional for tle leached anilite by microprobe approximately the same as that of geerite mined analysis is indicated on the composition axis. one reflection of the D doublet Cut..S. In fact, Sourcesof data are as in Figure 1. (Dr in Fig. 38) has a spacing correspondinq to an ideal itru"turul composition of Cur.oS. This spac- structure represents the lowest possible Cu:S For leached anilite, the sulfur-to-sulfur (R) one of ratio that still retains the cubic close-packing ing in the close-packedlayers and layers (Dr) are of sulfur atoms characteristic of Group-l copper the spacings between these How- sulfides (Goble 1977, in prep.). This reflection consistent with the analyzed composition. between the in tle doublet has a spacing consistent with ever, the overall average spacing (D') with this the majority of reflections in this orientation sulfur layers is not consistent 'reciprocal most probable e-x- of the lattice. The spacing analyzed composition. The 9f -the changes in the second reflection of the D doublet (Dr in Fig' planation for these observed upon loss of 38) is anomalous in this opientation, but is anitite structure is that anilite, changes--inlo consistent with the R reflection in indicating copper through artificial leaching, geerite structure. With a composition of Cur.re-r.rrS,very close the a material hiving the ,to 'removal from the material, analyziA composition of Cur.or-r.roS.Natural further of copper (R) in this structure madrial in this compositional range has the sulfur-to-sulfur distance remains metastably hexagonal structure of yarrowite Cur.r$, a decrease, but the material Some formation of struclture distinctly different from that of geerite' in the geerite structure. THE CANADIAN MINBRALOCIST covalent sulfur-sulfur bonds such as those ob_ (1980), to served in covelline, be metastable.Inasmuch as potter,s yarrowite anO spionilopite identification may occur, but of these phases was based upon these covalently tonOid-orJ"rJ'io,o sulfur_ X-ray powder-diffraction sulfur pairs are not sufficienily and microprobe anal_ planes yses, the possibility exists that he was in fact parallel to one anothei to form'tle looking at varieties of the metastable structure hexagonal structures observeJ io tfr"r"-ili"erur.. of. geerite (or of leached anilite) detected in Therefore, the spacings of the R ,"n"cdo"- aoO this rather tlan at yarrowite and one of the D doublet (Ds) accurateryon""t investigation tn" spionkopite. [potter recognized that actual composition of the material, one of his ,h"r"^ tl" blauNeibend covellines htd of the other reflection a digenite_like struc- 1p_acing of tln" a aor.rUt"t ture and suggested that blaubleibend 1Dt) reflects the ideal comporition covellines oi-'tu. form because of the difficulty structure of the material. This-interpretation in nucleating is normal covelline with its hexagonal reinforced by the observation of close_packed C6ffe ifpzZ, structure.l Therefore, his in- p1ep.) that the analyzed conclusion that blau- of bleibend covellines of compositions spionkopite and geerite viry "o-poriii-, Cur.rS and from tne struciurar Cur.nS are metastable phases compositions determined using in the system Figure 5 and copper*sulfur becomes other structural data. ambiguous; one may reasonably Examination postulate that yarrowite Cur.nS and of the X-ray powder data prc_ spionkopite sented in Table Cur.$ are stable phasesin the system 3 reveals one other i-- copper-sulfur, portant feature ""- whereas the leached anilite-type about the structure of leached synthetic phases anilite. P._owderpatterns Cur.rS and Cur.aS are meta- of leached uoilil; ar" stable. very similar to the powder patteros of varrowite and of synthetic blaubleibend covellins5 D,r._ pared AcrNowr,sDcsMENTs by such workers as Rickard (197A ind Frenzel (1959). Goble (1980) na, snowl tlar The author is grateful to Dr. M.I. Corlett yarrowite, one tyqg of. btaubleibend covelline, (Queen's University) for discussions, supervi- has a structure distinctly different from that sion and assistancewith the ph.D. thesis-from shown here for leached anilite. Juaeins-fiom which this material is taken. The many discus- the powder data of Table 3 alone, it i-s A"itficuft sions I had with Dr. J.D. Scott (illdorado to say whether in fact thce previous workers Nuclear) and Dr. G.W. Robinson synthesized material having concerning a structure similar the possible nature to leached anilite of the structure of the or to yarrowite, particularly leached anilite phase with the characteristically and its relationship to weak and'diffuse re_ other,copper sulfide flections observed structures were of parti- in th6se phases. An impor_ cular help. tant consequenceis that powder patterns alone are not sufficient to identify synthetic blaublei- RerunBNcss b.end covellines. Two possible methods of posi_ tive identification are suggested: l) sinele_ Bennv, L.G. (1954): The crystal crystal X-ray patterns structure of of. blaubleibend covellines covelline, CuS, and klockmannite, CaSr,, Amer. yill. e_xhi!i1 hexagonal symmetry, whereas Mineral. 39, 504-509. leached anilite-type phases will not-unless thev DoNNAy, G., hrNev, J.D.H. are (2) on polished sections, D/az_ & Kur-r,nnuo, G. -twinned; (1958): Crystal and twia structure bleibend covellines have extinction parallel of digenite, to CusS5.Amer. Mineral. 4r, Z2B-242. the cleavage, whereas leached inilite-Wpe phases will not rntess they are trrinned. Fbr EveNs,H.T., Jn. (1971): Cyystal structureof low fine grained, artificially precipitated material chalcocite. Nature 282, 69-70. lqcl as that produced by the method of FneNznr, G. (1959): Idait und ..blaubleibender Rickard (1972), differentiation of blqubteibend Covellin". Neues lahrb. Mineral. Abh. gg, E7- covelline and the leached anilite-type phase will r32. be particularly difficult, it not impossibte. Gonr-n, (1977); The Mineralogy,Composition, This uncertainty in l.J. the structural identifica_ ayd Crystal Structure of Selected Copper tion of synthetic Sul_ analogues of. the blaubleibend phides lrom the Belt-purcell Sapergroip, South- covellines is of particular interest when applied westAlberta, Canoda,ph.D. thesis,queen,s Univ., to the work of potter (1977). potter s66wea Kingston, Ontario. the synthetic material of compositions Cur.rS (1980): and Cur.aS, corresponding Copper sulfides from Alberta: compositionally to yarrowite Cue,Sr the minerals and spionkopite CuseSz".Can. yarrowite and spionliopite of dobb Mineral. 18, 511-51E. THE LEACHING OF COPPER FROM ANILITE 59r

& Rourxsox, G. (1980): G€€rite, Cur.eoS, PorrER, R.W. II (1977): An electrochemicalin- a new copper sulfide from deKalb Tovnship, vostigation of the system copper-zulfur. Econ. New York. Can, MineraL lS' 519-523. Geol. 72, 152+1542, KuLLERUD,G. (1965): Covellite stability relations & Evexs, H.T., Jr. (1976): Definitive in the CuJ $ystem. Freiberger Forschangshelte X-ray power data for covellite, anilite, djurleite, c186, 145-160. and chalcocite.,1. Res. U. S- Geol. Surv. 4' 205-212. Mon, G.H. (1964): Blaubleibendercovellite. Car' negie Inst. Wash.'Year Book 68' 2A8-2A9, Rrcre*o, D:f . 1o972): Covellite formation in low lemperatureaqueous solutions. Mineral. Deposita Monrrvrom, N. & Koro, K. (1970): Phase rela- 7, 18G.1E8. tions of tle Cu-S system at low temperatures: stability of anilite. Amer. MineraL 5S, 106-117. RosEBooM,E.H., Jn. (1966): An investigatiouof the system-between Clr-S and some natural, oopller $rl- & Smuearr, Y. (1969): Anilite, fides 25' and 700'C. Econ. Geol, 61, CurSn,a new mineral. Arner. Mineral. 54, 1256' 64t-672. 1268. & Kur,r,nnuo, G. (1963): Polymorphism Received Aprll 1981, revised manuscript accepted in digenite. Amer. Minerat. 48, nA'123. September 19E1,