1155
The Canadian Mineralogist
Vol. 41, pp. 1155-1166 (2003)

KUPČÍKITE, Cu3.4Fe0.6Bi5S10, A NEW Cu–Bi SULFOSALT FROM FELBERTAL,
AUSTRIA, AND ITS CRYSTAL STRUCTUREDAN TOPA§
Mineralogical Institute, University of Salzburg, Hellbrunnerstr. 34/III, A-5020 Salzburg, Austria

EMIL MAKOVICKY AND TONČI BALIĆ-ŽUNIĆ
Geological Institute, University of Copenhagen, Øster Voldgade 10, DK–1350 Copenhagen K, Denmark

WERNER H. PAAR
Mineralogical Institute, University of Salzburg, Hellbrunnerstr. 34/III, A-5020 Salzburg, Austria

ABSTRACT
Kupčíkite, Cu3.4Fe0.6Bi5S10, a new mineral species, is found in the scheelite deposit of Felbertal, Austria, in a quartz gangue,
in association with chalcopyrite, pyrrhotite, molybdenite, sphalerite and native bismuth, intergrown with makovickyite,
cupromakovickyite, hodrushite, cuprobismutite and derivatives of the bismuthinite–aikinite series. The mineral is grey withmetallic luster, brittle, and without cleavage. Mean micro-indentation hardness is 192 kg/mm2 (Mohs hardness 3.3), and thecalculated density is 6.42 g/cm3. In reflected light, it is grayish white; the anisotropy is moderate in air and strong in oil, and it
does not show internal reflections. Reflectance values (in %) in air are, for R1 and R2, 33.55, 40.56 at 470 nm, 33.92, 41.14 at 546
nm, 34.16, 41.35 at 589 nm, and 34.2, 41.32 at 650 nm. The average results of seven electron-microprobe analyses are: Cu 13.02,
Fe 2.23, Ag 0.11, Cd 0.3, Bi 64.21, Sb 0.12, S 20.10, total 100.08 wt.%, corresponding to Fe0.64Cu3.29Ag0.015Cd0.045Sb0.015
Bi4.94S10.07 (basis: 19 atoms per formula unit). The simplified formula, in accordance with the crystal-structure analysis, is
Fe0.6Cu3.4Bi5S10. The crystal structure was solved, to R = 4.1%, from single-crystal data obtained on a four-circle diffractometerwith an area detector. Kupčíkite has a monoclinic cell with a 17.512(2), b 3.9103(4), c 12.869(1) Å,  108.56(1)°, V 835.4(1) Å3,
space group C2/m, with Z = 2. The strongest lines in the calculated powder-diffraction pattern [d in Å (I)(hkl)] are: 6.028(4)(201),
3.596(7)(401), 3.213(4)(2̄04), 3.128(10)(112), 3.071(7)(3̄12), and 2.683(5)(113). Its structure corresponds to the structure ofsynthetic Cu4Bi5S10; the (Cu,Fe) position in the mineral is distinctly split. Kupčíkite is closely structurally related to cuprobismutite
and hodrushite. It is the N = 1 member of the cuprobismutite series, whereas cuprobismutite is the N = 2 member. Hodrushite iscomposed of a regular 1:1 intergrowth of kupčíkite-like and cuprobismutite-like layers. In typical intergrowths with makovickyite
or hodrushite, kupčíkite shows sharp straight boundaries with both of these phases, but where in contact with derivatives of thebismuthinite–aikinite series, the latter replace kupčíkite. In a rare occurrence of kupčíkite with cuprobismutite in the same aggregate, the cuprobismutite is replaced by kupčíkite.
Keywords: kupčíkite, single-crystal X-ray diffraction, electron-microprobe analyses, cuprobismutite homologous series, Felbertal
deposit, Austria.

SOMMAIRE
Nous avons découvert la kupčíkite, Cu3.4Fe0.6Bi5S10, nouvelle espèce minérale, dans le gisement de scheelite de Felbertal, enAutriche, dans une gangue de quartz, en association avec chalcopyrite, pyrrhotite, molybdénite, sphalérite et bismuth natif, enintercroissances avec la makovickyite, la cupromakovickyite, la hodrushite, la cuprobismutite et des dérivés de la série
bismuthinite–aikinite. Il s’agit d’un minéral gris avec éclat métallique, cassant, et sans clivage. En moyenne, les micro-indentations indiquent un dureté de 192 kg/mm2, équivalente à un dureté de Mohs de 3.3, et la densité calculée est 6.42 g/cm3. En lumière
réfléchie, la kupčíkite est blanc grisâtre; l’anisotropie est modérée dans l’air et forte dans l’huile. Elle ne montre aucune réflexion
interne. Les valeurs de la réflectance R1 et R2 dans l’air sont 33.55, 40.56% à 470 nm, 33.92, 41.14% à 546 nm, 34.16, 41.35%
à 589 nm, et 34.2, 41.32% à 650 nm. Sept analyses à la microsonde électronique ont donné, en moyenne, Cu 13.02, Fe 2.23, Ag
0.11, Cd 0.3, Bi 64.21, Sb 0.12, S 20.10, total 100.08% (en poids), ce qui correspond à Fe0.64Cu3.29Ag0.015Cd0.045Sb0.015Bi4.94S10.07
sur une base de 19 atomes par unité formulaire. La formule simplifiée, en concordance avec les résultats de l’ébauche de lastructure cristalline, est Fe0.6Cu3.4Bi5S10. Nous en avons résolu la structure jusqu’à un résidu R de 4.1% à partir de données§

E-mail address: dan.topa@sbg.ac.at1156

THE CANADIAN MINERALOGIST

obtenues sur monocristal avec un diffractomètre à quatre cercles et un détecteur de type CCD. La kupčíkite possède une maillemonoclinique, a 17.512(2), b 3.9103(4), c 12.869(1) Å,  108.56(1)°, V 835.4(1) Å3, groupe spatial C2/m, avec Z = 2. Les six
raies les plus intenses du spectre de diffraction calculé [d en Å (I)(hkl)] sont: 6.028(4)(201), 3.596(7)(401), 3.213(4)(2̄04),
3.128(10)(112), 3.071(7)(3̄12), et 2.683(5)(113). Sa structure correspond à celle du composé synthétique Cu4Bi5S10; la position(Cu,Fe) du minéral, par contre, est distinctement scindée. La kup číkite montre une relation structurale étroite avec lacuprobismutite et la hodrushite. Elle est l’homologue N = 1 de la série de la cuprobismutite, tandis que la cuprobismutite en est
le membre ayant N égal à 2. La hodrushite est composée d’une intercroissance régulière 1:1 de couches de type kupčíkite et
cuprobismutite. Dans les intercroissances typiques avec la makovickyite ou la hodrushite, la kupčíkite fait preuve d’interfaces
rectilignes et franches avec ces deux phases, mais en contact avec les dérivés de la série de la bismuthinite–aikinite, ces derniers
la remplacent. Dans un rare exemple de kupčíkite avec cuprobismutite dans le même aggrégat, la cuprobismutite se voit remplacéepar la kupčíkite.
(Traduit par la Rédaction)
Mots-clés: kupčíkite, diffraction X sur monocristal, analyses à la microsonde électronique, série d’homologues de lacuprobismutite, gisement de Felbertal, Autriche.

INTRODUCTION
Copper and bismuth together form a series of complex sulfides that have various stoichiometries and distinct structures; in many instances, minor amounts ofother elements seem essential for their formation, especially under natural conditions. At the Cu-rich end, thisseries starts with wittichenite, Cu3BiS3, whose crystal
structure was determined by Matzat (1972) and Kocman& Nuffield (1973). It continues with emplectite, CuBiS2(structure by Portheine & Nowacki 1975), hodrushite[Kupčík & Makovicky (1968), Kod ěra et al. (1970); thechemical composition was given as Cu8.1Fe0.3Bi11.5S22,
with Pb attributed an uncertain role by Makovicky &MacLean (1972)] and cuprobismutite [Nuffield (1952),
Taylor et al. (1973); Cu10.4Bi12.6S24 for the synthetic,
Ag-free analogue; structure by Ozawa & Nowacki(1975)] and ends with the Cu–Bi-based homologues ofpavonite: N = 4, makovickyite (Mumme 1990, Žák etal. 1994) and N = 8, mummeite (Karup-Møller &Makovicky 1992, Mumme 1990). The N = 4 homologueof pavonite, with a chemical formula Cu3.21Bi4.79S9, andan N = 3 homologue, Cu1.57Bi4.57S8, have also been described as pure synthetic Cu–Bi compounds (Tomeoka
et al. 1980).
Kupčíkite, the new natural Cu–Bi sulfosalt discovered at Felbertal, Austria, corresponds structurally to thesynthetic phase Cu4Bi5S10 (Mariolacos et al. 1975); its
discovery enriches further the spectrum of natural Cu–
Bi sulfosalts, reveals the first natural occurrence of thismember of the cuprobismutite homologous series(Makovicky 1989), and contributes to an understandingof the role of minor elements in Cu–Bi sulfosalts.
Kupčíkite has been named after Professor Vladimir
Kupčík (1934–1990), who was active at the Universityof Bratislava and the University of Göttingen, in acknowledgment of his outstanding contributions to the
crystal chemistry of sulfosalts in general, and his understanding of the principles determining the structuresof Cu–Bi sulfosalts in particular. The pronunciation of

the name in English is k-ou-p-tch-ee-kite, the diacritical signs respectively indicating a consonant tch and along vowel. The new mineral and its name have been
approved prior to publication by the IMA Commission
on New Minerals and Mineral Names (IMA 2001–017).
The holotype material is deposited at the Geological
Institute and Geological Museum, University of
Copenhagen, Denmark, and a cotype is in the referencecollection of the Mineralogical Institute, University ofSalzburg, Austria (catalogue no. 14933).

APPEARANCE AND PHYSICAL PROPERTIES
Rare elongate aggregates that are intergrowths ofkupčíkite with makovickyite or bismuthinite derivatives
in the range krupkaite–aikinite, as well as the less common parallel intergrowths of kupčíkite with hodrushite,
do not exceed 0.5 mm in size. Kupčíkite is grey, opaquewith a metallic luster. It is brittle, with an uneven fracture. No cleavage or parting was observed, as in the related hodrushite (Kod ěra et al. 1970). The bulk ofmaterial is a fine-grained quartz gangue with parallel
strings of sulfides, especially chalcopyrite, pyrrhotite,molybdenite, occasional sphalerite and native bismuth.
The micro-indentation hardness was measured with
six indentations on two grains, using a VHN load of
50 g. The mean value obtained is 192 kg/mm2, range
179–210 kg/mm2, yielding a calculated Mohs hardnessof 3.2–3.4. These values are comparable to the values
obtained on hodrushite from Banská Hodruša, Slovakia:
mean value 200 kg/mm2 (range 187–213), i.e., 3.7 on
the Mohs scale (Kod ěra et al. 1970); a 20-g load wasused in the latter investigation.
In reflected light, kupčíkite is grayish white; internal reflections are absent. The anisotropy is moderatein air and strong in oil; the bireflectance is perceptible
in air, and moderate in oil. The pleochroism of kupčíkite
is weak in air, white with bluish tints, and enhanced inoil. The rotation tints between polars are dark bluishgray to yellowish brown for the most anisotropic grains.

KUP ČÍKITE, A NEW Cu–Bi SULFOSALT FROM FELBERTAL, AUSTRIA

Quantitative data on reflectance were obtained in air;
we used a WTiC standard and Leitz MPV–SP microscope photometer (Table 1, Fig. 1). The measured values of Rmax (in air) coincide with those of hodrushite
and cuprobismutite from Felbertal (D. Topa, unpubl.
data), whereas the Rmin values (in air) are on average
2.5% lower than those of cuprobismutite and almost 2%
lower than those of hodrushite. Both kupčíkite curves
display only a very flat maximum of ~1% at about 625
nm, in agreement with the white color of the mineral.

CHEMICAL DATA
Quantitative chemical data for kupčíkite and the associated sulfosalts were obtained with an electron microprobe (JEOL Superprobe JXA–8600, controlled by
LINK–eXL system, operated at 25 kV, 30 nA, 20 s
counting time for peaks and 7 s for background). The
following natural (n) and synthetic (s) standards and Xray lines were used: n-CuFeS2 (CuK), s-Bi2S3 (BiL,SK), n-PbS (PbL), s-CdTe (CdL, TeL), n-Sb2S3(SbL) and pure metal for AgL. The raw data werecorrected with the on-line ZAF–4 procedure. Standard
deviations of concentrations of the elements sought(error in wt.%) for the cuprobismutite series fromFelbertal deposit are: Bi 0.17, Pb, Cd and S 0.06, Cu
0.04, Ag 0.03, Sb 0.02 and Fe 0.01. The only minor elements detected in kupčíkite are Cd, Ag, Pb and Sb.
Results of three to five point analyses obtained froma homogeneous grain or an individual phase in an aggregate were averaged. These mean compositions arecompiled in Tables 2a, 2b and 2c. Empirical formula ofkupčíkite, normalized to 19 atoms per formula unit
(apfu), which is the content of the two asymmetric units
as determined by the structure analysis, is:1157

ture refinement under the conditions specified below.
The simplified formula of kupčíkite is Cu+3.4Fe3+0.6
Bi5S10.

X-RAY-DIFFRACTION DATA
The limited amount of material, commonly intergrown with other sulfosalts, and the small size of thecrystals extracted, limited the X-ray studies to the useof a single-crystal diffractometer with an area-detector
system (Table 3). Kupčíkite is monoclinic, space groupC2/m, with two of its unit-cell parameters, a and b, very
close to those of cuprobismutite and hodrushite; theyalso coincide with those of two synthetic compounds(Table 4). The table of structure factors may be obtained
from the Depository of Unpublished Data, CISTI, National Research Council, Ottawa, Ontario K1A 0S2,
Canada. As powder data could not be obtained because
of insufficient material, a theoretical powder pattern was
calculated with PowderCell 2.3 software (Kraus &Nolze 1999) for Debye–Scherrer geometry and CuKradiation ( 1.540598 Å), without the anomalous dispersion correction (Table 5). Cell parameters, spacegroup, atom positions, site occupancies and isotropic
displacement factors were taken from the results of thesingle-crystal refinement of the structure.

CRYSTAL-STRUCTURE ANALYSISThe crystal structure was solved by direct methods.
Among the 13 highest maxima in the E-Fourier map,ten were shown to be the real atom-positions. The assignment of positions was based on typical interatomic
distances [Bi–S in the range 2.6–3.5 Å, Cu(Fe)–S in therange 2.3–2.9 Å]. The assignments were confirmed by

Cu3.29Ag0.02Fe0.64Cd0.04(Bi4.94Sb0.02)4.96S10.06
or(Cu3.29Fe0.64)3.93(Bi4.94Sb0.02Ag0.02
Cd0.04)5.02S10.06
The empirical formula was matched by the model composition Cu3.4Fe0.6Bi5S10 obtained in the crystal-struc-

FIG. 1. Reflectance data for kupčíkite (䊊), hodrushite (䉫)and cuprobismutite (䉭) from Felbertal.

1158

THE CANADIAN MINERALOGIST

subsequent least-squares refinements, and 3 Bi, 2Cu(Fe)and 5 S positions were confirmed. The scattering factors for neutral atoms were used for all elements. Oneof the Cu(Fe) positions appeared split in a differenceFourier map and was further refined as two distinct Cu
positions with independent occupancies and isotropic
displacement factors. All other positions were refined
anisotropically, and with full occupancies (except for
the Cu1 position, with a free occupancy). The three Cu

positions refined to occupancies 0.96 (Cu1), 0.69 (Cu2),
and 0.25 (Cu3). Thereafter, a mixed (Cu,Fe) occupancy
was defined for Cu2 and Cu3 sites with a constraint offull occupancy for Cu2 + Cu3 combined. Furthermore,
the coordinates and the atom-displacement parameters
for Cu and Fe in the same position were constrained tohave identical values. The occupancy of Fe in Cu3 refined to null, and the iron was therefore excluded fromthis position in the last cycles and confined to the Cu2

KUP ČÍKITE, A NEW Cu–Bi SULFOSALT FROM FELBERTAL, AUSTRIA

1159

ues are negligible, and the Fe occupancy obtained isunrealistic, the model with iron at two copper sites was
discarded. After the final cycle of refinement, the largest matrix-correlations were between the x coordinatesof (Cu,Fe)2 and Cu3 sites (in the direction of splitting),
their occupancies and displacement factors (all between
0.85 and 0.6 absolute). All others correlations were
below 0.6. The final atom-parameters are listed inTable 6; atom positions are illustrated in Figure 2.

DESCRIPTION OF THE STRUCTURE
The structure of kupčíkite (Fig. 3) is almost identical to that of the synthetic iron-free Cu 4 Bi 5 S 10
(Mariolacos et al. 1975). The only difference concerns
the splitting of the one Cu position into two closely separated positions.
The structure is composed of two alternating typesof slabs (001), each about ½ unit cell wide. One type ofslab consists of double columns of square coordination

position. An additional attempt was made to introduce
Fe at the Cu1 site, and to refine the coordinates of Fe
and Cu at both sites independently (the displacement
factors were constrained to equal values per site). The
improvement in R values was marginal (R1 from 4.1%
to 4.0%, wR2 from 10.74% to 10.36%), whereas thesummary occupancy of Fe per asymmetric unit increased to 0.53 (1.06 per formula unit) compared to 0.29
(0.58) for the former. Because the differences in R val-

FIG. 2. Atom positions in kupčíkite. Length and orientationof unit-cell axes is indicated.

1160

THE CANADIAN MINERALOGIST

pyramids of Bi3, interconnected via common horizontal and inclined edges. These columns alternate withpairs of Cu1 tetrahedra. The latter can also be interpreted
as portions of paired trigonal coordination bipyramidswith Cu1 displaced toward the center of one pyramidand having a distorted tetrahedral coordination; the otherpyramid is empty. As already noted by Mariolacos etal. (1975), these slabs correspond fully to those foundin cuprobismutite and hodrushite.
The alternating layers can be described as thin (331)layers of the PbS archetype. They are composed of regular Bi1 octahedra flanked on two sides by square coordination pyramids of Bi2. The coordination of Bi2 iscompleted by S3 atoms from the first type of slab togive split octahedra or, alternatively, monocapped trigonal prisms. The cation positions between the [010] columns of Bi2–Bi1–Bi2 coordination polyhedra are split
into Cu2, Cu3 sites. The full Cu2, Cu3 coordination
polyhedron is a trigonal bipyramid. The cation positionin the bipyramid is split into a trigonal-planar site (Cu3),
and a distorted tetrahedral site (Cu2), situated inside thevolume of one of the pyramids.

COORDINATION POLYHEDRA
Whereas Bi1 occupies the center of an almost perfect octahedron of S atoms, the other two Bi atoms havesevenfold coordination in the form of a monocapped
trigonal prism, with the Bi atom situated close to theprism face facing the capping atom of sulfur. The lattercoordination is therefore transitional between a capped
trigonal prism and a “split” octahedron, in which one ofthe vertices is substituted by two vertices, converting
half of the coordination octahedron into a trigonal prism.
The central cation remains in the square face below thecap (Makovicky & Balić-Žunić 1998). As can be seenfrom Figure 2 and from the coordination parameters(Table 7), the Bi2 site is closer to the latter type, because the central atom lies closer to the plane of four S
atoms, and the coordination polyhedron has a lower
volume-distortion parameter than that of Bi3 (a characteristic of the “split” octahedron when compared to themonocapped trigonal prism: Makovicky & Balić-Žunić
1998).
Cu1 and Cu2 positions are tetrahedraly coordinated,with the central atom displaced toward one of the faces,
as is characteristic for Cu+ in sulfides. The positions
have practically equal average distances to the coordinated S atoms, and the spheres circumscribed to the tetrahedra have practically equal radii. The tetrahedronaround Cu2 is, however, more regular and thus has aslightly larger volume. The Cu3 position is in a trigonal
planar coordination, occupying one of the faces of the
Cu2 coordination tetrahedron. The Cu2 and Cu3 positions are very close to each other (0.46 Å), with partial
occupancies summing to a full one. As mentioned earlier, the full coordination of this cation site in the structure is trigonal bipyramidal if the more distant S1 atoms

also are included in the coordination polyhedron. The
same is true for the Cu1 position if the more distant S3
atoms are included. The refinement of the (Cu,Fe) occupancies in the three distinct positions suggests a preference of Fe for the Cu2 site.
Bond distances, angles and the characteristic parameters of the polyhedra for Bi and Cu(Fe) coordinations
are represented in Table 7.

THE ROLE OF FE IN THE STRUCTURE
As can be concluded from the chemical and structural analysis, Fe substitutes for part of the Cu in the
structure. The refinement of element occupancies in theCu1, Cu2, and Cu3 sites suggests a preference of Fe for
the Cu2 site, and an avoidance of the Cu3 site. We note,however, that the sensitivity of the refinement based on
the available X-ray-diffraction data is probably not sufficient for a definite conclusion about the occupancy
preferences. Bond-valence calculations based on theapproach of Brown & Altermatt (1985) and Brese &O’Keeffe (1991), with Fe variously distributed between
the Cu2 and Cu3 positions, did not help in either supporting or refuting the inference derived from the structure refinement. The valence of the S atoms refined tosimilar values in all models. The only positive information is that the valence sum for each of the (Cu,Fe) sites
suggests a valence close to 1 for Cu, and between 2 and3 for Fe.
If we assume Cu+ and Fe2+ in the formula obtainedby the chemical analysis, a valence deficit is obtainedfor cations, and we should assume that some of them
are in the higher valence-state. In this case, Fe3+ is assumed to be present, on the basis of an analogy withchalcopyrite Cu+Fe3+S2 (Greenwood & Whitfield 1968),
bornite Cu+5Fe3+S4 (Vaughan & Burns 1972), and a
low-iron synthetic tetrahedrite Cu + 11 Fe 3+ Sb 4 S 13
(Makovicky et al. 1990), all of which were examinedby Mössbauer spectroscopy. If all the Cu in kupčíkite is
assumed to be monovalent, the valence of iron in theformula obtained by chemical analysis calculates to
2.95, and its idealized formula is Cu+3.5Fe3+0.5Bi5S10.

KUP ČÍKITE, A NEW Cu–Bi SULFOSALT FROM FELBERTAL, AUSTRIA

1161

FIG. 3. The crystal structure of kupčíkite projected along [010]. In order of decreasing size the circles indicate S, Bi and Cu.
Two atomic levels, 2 Å apart, are indicated by shaded and empty circles, respectively. Cu2 (green) represents a mixed (Cu,Fe)
position. Two layers, combining paired coordination pyramids of Bi with Cu tetrahedra (shaded), and one (331)PbS layer, areindicated.

The splitting of the (Cu2,Cu3) position in the ratio
0.74:0.26 is probably not caused by the presence of Fe
in the structure. Although the amount of the Cu3 site
recalculated as a pure Fe site gives approximately thesame amount of Fe as found by chemical analysis, therefinement suggests Fe to be completely excluded fromthis site; moreover, a very similar split in the Cu coordination is observed in the structures of Cu4Bi4S9 (Bente& Kup čík 1984) and Cu4Bi4Se9 (Makovicky et al.
2002), where no Fe is present. In the latter two structures, all the Cu is in a monovalent state (the structurescontain a disulfide and a diselenide group, respectively,
and the valences of cations and anions sum to 16 valence units per formula unit), so that the splitting cannot
be attributed to the various valence states of Cu either.
The same kind of splitting was not reported for the synthetic Cu4Bi5S10 (Mariolacos et al. 1975), in which bothCu sites have been refined as one and fully occupied.
To satisfy the stoichiometry, one-quarter of the Cushould be in a divalent state, amounting to one-half of astructural site. The Cu2 site of Mariolacos et al. (1975)

corresponds to the present Cu1 site, in terms of both its
position in the structure and its coordination. Their Cu1
is in a position equivalent to that of the present (Cu2,
Cu3). Interestingly, it has coordination characteristics
intermediate between the two. It is difficult to make adefinite conclusion about this difference, but we believethat a split of this Cu site in Cu4Bi5S10, also indicatedby its augmented displacement-factor, could have been
overlooked owing to the lower resolution of the data (theR factor obtained in that study was 12.2%).

RELATED SPECIES
Kupčíkite is the N = 1 member of a cuprobismutite
homologous series (Makovicky 1989). The N = 2 member is cuprobismutite, which differs from kupčíkite bya greater thickness of the PbS-like portions of the structure, or, in terms of a polyhedron-based description, by
the attachment of two coordination pyramids of Bi to aside of the central Bi octahedron instead of only one
pyramid, as in kupčíkite. Remarkably, the first struc-1162

THE CANADIAN MINERALOGIST

ture of the series to be determined was that of hodrushite(Kupčík & Makovicky 1968), which is a regular 1:1
intergrowth of N = 1 and N = 2 layers, i.e., it has
kupčíkite-like and cuprobismutite-like modules in regular alternation. It lacks the fractionally occupied (Cu,Bi)
sites observed in synthetic, pure end-member cuprobismutite (Ozawa & Nowacki 1975), with the problemsof charge balance apparently taken care of by incorporation of minor cations. The same way of charge balancing has been observed by us for natural kupčíkite,

cuprobismutite and hodrushite from Felbertal (Topa etal., in prep.). The composition of the hodrushite structure from two regularly alternating layers, one with acuprobismutite-like cell and the other without an analogue at the time of publication, was clearly suggested
by Koděra et al. (1970), who likened the situation tothat in the sartorite homologous series, already known.
The synthetic compound Cu4Bi5S10, fully analogous
to kupčíkite, and structurally analyzed by Mariolacos etal. (1975), was synthesized at 340°C. As stated above,

KUP ČÍKITE, A NEW Cu–Bi SULFOSALT FROM FELBERTAL, AUSTRIA

the charge-balance problems in it must be compensatedfor by the presence of a certain amount of divalent copper. Mariolacos et al. (1975) also gave a more detailed
discussion of the structural relations between Cu4Bi5S10,
cuprobismutite and hodrushite, along the lines alreadysuggested by Kupčík & Makovicky (1968) and Kod ěra
et al. (1970).
The closest analogue to natural kupčíkite is the synthetic phase Z, prepared by Sugaki et al. (1981) at 300

1163

and 420°C. It was given with a formula Cu8.4Fe1.2
Bi10.8S22, analogous to hodrushite, although its unit-cellparameters (Table 4) are practically identical to thoseof Cu4Bi5S10 (i.e., of only the kupčíkite-like componentof the hodrushite structure; the recalculated formula is
Cu3.8Fe0.5Bi4.9S10). Characteristically, this phase cancoexist with synthetic cuprobismutite and has in somecases smaller amounts of iron than kupčíkite. The above
formula is almost identical to that of kupčíkite and as-

1164

THE CANADIAN MINERALOGIST

sumes Fe3+. The iron content (in wt.%) in the threecuprobismutite homologues that coexist in the Felbertal
deposit can be seen in Figure 4, reflecting the fact that
Fe can be accommodated only in the kupčíkite-likemodule. The content of silver in these homologues isinversely proportional to that of iron. A discussion of
the role and place of Ag in these structures will be a
topic of an upcoming contribution.

MINERAL ASSOCIATIONS
Kupčíkite was found in two distinct orebodies, K7
and K8, respectively, of the Felbertal scheelite deposit,
situated in the Tauern Window of the Austrian Alps.
These orebodies, most distal in respect to the rest of thedeposit, lie in diverse types of amphibolite with lenses
of leucocratic gneisses and, in the case of the K8
orebody, also quartz masses. For a concise summary of
the geology and mineralogy of the deposit, the reader isreferred to Topa et al. (2002). The ore association isconsidered a product of polyphase Variscan magmatic
events; it was subsequently reworked during a prograde
episode of Alpine metamorphism, followed by retrograde metamorphism.
In both orebodies, kupčíkite nearly invariably occurs
in a typical mineral association kup číkite – makovickyite (the pavonite homologue 4P, either as a low-Cu
variety or with exsolution lamellae of cupromakovickyite) – bismuthinite derivatives (bd) (Fig. 5). The
composition of the latter is 50 < naik < 62, and only rarely
higher. In our short-hand notation, we write in what
follows the content of the aikinite component as a subscript to bd. Only rarely can a replacement product with

low naik be observed at the margins of the aggregate, or
between the bismuthinite derivative and other sulfosalts.
Occasionally, homogeneous cupromakovickyite[4P(Cu,Pb)] is present in parallel growth with makovickyite (Table 2b, Fig. 5a). Kupčíkite was found inseveral instances also in association with hodrushite (asparallel intergrowths), associated mostly with bd~55,
only exceptionally with bd~88.
In the kupčíkite – hodrushite intergrowths from theFelbertal deposit, these phases, commonly multiplyintergrown, retain their compositional integrity, resulting in sharp straight boundaries without transitional
compositions (Figs. 5a, c). Contacts of kupčíkite withmakovickyite (4P) display straight crystal faces as well(Fig. 5b), whereas in all intergrowths with interpretabletextures, the bismuthinite derivative (bd50–96, less commonly also the late-formed bismuthinite derivative withnaik ≤ 50) replaces kupčíkite (Figs. 5b–d). It replaces
makovickyite as well. Most of these intergrowths ofthree to four sulfosalt phases come from thin quartz layers in the metamorphic rock and were slightly replaced
from the margins by quartz or sulfides (Figs. 5c, e).
The rare occurrence of kupčíkite and cuprobismutite
in one aggregate is characterized by the replacement of
the latter by the former. This replacement is associatedwith, or followed by, a replacement of both phases by
bd92–94 (Figs. 5c, d). In one instance, the bismuthinite
derivative that formed after partly replaced kupčíkite has
a value of naik = 79, and was followed by a phase withnaik = 92.

ACKNOWLEDGEMENTS
This project was supported by grants of the State
Research Council of Denmark and by a grant to D. Topaby the University of Salzburg. The manuscript benefitted from the comments of Drs. A. Pring and P. Berlepsch
and the editorial care of Robert F. Martin.

FIG. 4. Iron content (wt.%) in the minerals of the cuprobismutite series from Felbertal versus homologue number.
Symbols: kup číkite (䊊), hodrushite (䉫) and cuprobismutite (䉭).

FIG. 5. Sulfosalt associations of kupčíkite in Felbertal. BSE
photographs, bar indicates 100 m. (a) Kupčíkite (ku) andhodrushite (ho) partly replaced by bismuthinite derivative(n aik = 56) with relict lamellae of low-Cu ( 4P) andcupromakovickyite [4P(Cu,Pb)]. (b) Kupčíkite and makovickyite; the former is replaced by bd52, the latter by native
bismuth (bi). (c, d) Kupčíkite replacing cuprobismutite(cu); both phases are in turn replaced by bd79–92. Quartz
gangue and sulfides partly replace sulfosalts from periphery. (e, f) Three-phase aggregates of makovickyite (withexsolution lamellae of cupromakovickyite) – bd56–58 –kupčíkite. In both cases, minor hodrushite is present. Selective replacement, especially of makovickyite, from theaggregate’s periphery is observed, primarily in (e).

KUP ČÍKITE, A NEW Cu–Bi SULFOSALT FROM FELBERTAL, AUSTRIA

1165

1166

THE CANADIAN MINERALOGISTREFERENCES

to the structures of hodrushite and cuprobismutite. Acta
Crystallogr. B31, 703-708.

BALIĆ-ŽUNIĆ, T. & MAKOVICKY, E. (1996): Determination of
the centroid or “the best centre” of a coordination polyhedron. Acta Crystallogr. B52, 78-81.

MATZAT, E. (1972): Die Kristallstruktur des Wittichenits,
Cu3BiS3. Tschermaks Mineral. Petrogr. Mitt. 18, 312-316.

BENTE, K. & KUpčÍK, V. (1984): Redetermination and refinement of the structure of tetrabismuth tetracopper enneasulphide, Cu4Bi4S9. Acta Crystallogr. C40, 1985-1986.

MUMME, W.G. (1990): A note on the occurrence, compositionand crystal structures of pavonite homologous series members 4P, 6P and 8P. Neues Jahrb. Mineral., Monatsh., 193204.

BRESE, N.E. & O´KEEFFE, M. (1991): Bond-valence parameters
for solids. Acta Crystallogr. B47, 192-197.
BROWN, I.D. & ALTERMATT, D. (1985): Bond-valence parameters obtained from a systematic analysis of the inorganic
crystal structure data base. Acta Crystallogr. B41, 244-247.
GREENWOOD, N.N. & WHITFIELD H.J. (1968): Mössbauer effect studies on cubanite (CuFe2S3) and related iron sulphides. J. Chem. Soc. (A), 1697-1699.
KARUP-MØLLER, S. & MAKOVICKY, E. (1992): Mummeite – a
new member of the pavonite homologous series from
Alaska mine, Colorado. Neues Jahrb. Mineral., Monatsh.,
555-576.
KOCMAN, V. & NUFFIELD, E.W. (1973): The crystal structureof wittichenite, Cu3BiS3. Acta Crystallogr. B29, 25282536.
KOD ĚRA, M., KUP ČÍK, V. & MAKOVICKÝ, E. (1970): Hodrushite– a new sulphosalt. Mineral. Mag. 37, 641-648.
KRAUS, W. & NOLZE, G. (1999): Powder Cell for Windows(version 2.3). BAM, Berlin, Germany.
KUP ČÍK, V. & MAKOVICKY, E. (1968): Die Kristallstruktur desMinerals (Pb,Ag,Bi)Cu4Bi5S11. Neues Jahrb. Mineral.,Monatsh., 236-237.
MAKOVICKY, E. (1989): Modular classification of sulphosalts– current status. Definition and application of homologous
series. Neues Jahrb. Mineral., Abh. 160, 269-297.
________ & BALIĆ-ŽUNIĆ, T. (1998): New measure of distortion for coordination polyhedra. Acta Crystallogr. B54,
766-773.
________, FORCHER, K., LOTTERMOSER, W. & AMTHAUER, G.
(1990): The role of Fe2+ and Fe3+ in synthetic Fe-substituted tetrahedrite. Mineral. Petrol. 43, 73-81.
________ & MACLEAN, W.H. (1972): Electron microprobe
analysis of hodrushite. Can. Mineral. 11, 504-513.

NUFFIELD, E.W. (1952): Studies of mineral sulpho-salts. XVI.
Cuprobismutite. Am. Mineral. 37, 447-452.
OZAWA, T. & NOWACKI, W. (1975): The crystal structure of,and the bismuth–copper distribution in synthetic cuprobismuthite. Z. Kristallogr. 142, 161-176.
PORTHEINE, J.C. & NOWACKI, W. (1975): Refinement of thecrystal structure of emplectite, CuBiS2. Z. Kristallogr. 141,387-402.
SHELDRICK, G.M. (1990): Phase annealing in SHELX-90: direct methods for larger structures. Acta Crystallogr. A46,
467-473.
________ (1997) SHELXTL Program Manual. Bruker AXS,
Madison, Wisconsin.
SUGAKI, A., KITAKAZE, A. & HAYASHI, T. (1981): Synthesis ofminerals in the Cu–Fe–Bi–S system under hydrothermal
condition and their phase relations. Bull. Minéral. 104, 484495.
TAYLOR, C.M., RADTKE, A.S. & CHRIST, C.L. (1973): New dataon cuprobismutite. J. Res. U.S. Geol. Surv. 1, 99-103.
TOMEOKA, K., OHMASA, M. & SADANAGA, R. (1980): Crystal
chemical studies on some compounds in the (Cu2S)–(Bi2S3)
system. Mineral. J. 10, 57-70.
TOPA, D., MAKOVICKY, E. & PAAR, W.H. (2002): Composition
ranges and exsolution pairs for the members of thebismuthinite–aikinite series from Felbertal, Austria. Can.
Mineral. 40, 849-869.
VAUGHAN, D.J. & BURNS, R.G. (1972): Mössbauer spectroscopy and bonding in sulphide minerals containing fourcoordinated iron. 24th Int. Geol. Congress (Montreal) 14,
158-167.
ŽÁK, L., FRYDA, J., MUMME, W.G. & PAAR, W.H. (1994):
Makovickyite, Ag1.5Bi5.5S9 from Bǎiţa Bihorului, Romania. The 4P natural member of the pavonite series. Neues
Jahrb. Mineral., Abh. 168, 147-169.

________, SØTOFTE, I. & KARUP-MØLLER, S. (2002): The crystal structure of Cu4Bi4Se9. Z. Kristallogr. 217, 597-604.
MARIOLACOS, K., KUP ČÍK, V., OHMASA, M. & MIEHE, G.
(1975): The crystal structure of Cu4Bi5S10 and its relation

Received March 28, 2003, revised manuscript accepted
August 17, 2003.