_TIBIOCLAUDETITEAsSB0 3
A NEW MINERAL FROMTSUMEB, NAMIBIA
Marcus J, Origlieri
Department of Geosciences, University of Arizona
Tucson, Arizona 85721-0077 USA
marcus@ mi neralzone.com
Robert T. Downs
Department of Geosciences, University of Arizona
Tucson, Arizona 85721-0077 USA
rdowns@u.arizona.edu
William W. Pinch
19 Stonebridge Lane, Pittsford, New York 14534 USA

Gary L. Zito
Department of Metallurgical and Materials Engineering
Colorado School of Mines, Golden, Colorado 80401 USA

Stibioclaudetite has been found at the Tsumeb mine, Namibia,
in bladed crystals to 6 mm association with leiteite, ludlockite,smithsonite and quartz. Previously identified specimens of claudetitefrom Tsumeb may well be stibioclaudetite instead.
ABSTRACT
Stibioclaudetite is a new mineral species with ideal chemistry
AsSb03• The mineral has monoclinic symmetry, P2 1/n, with a =4.5757(4) A, b = 13. t288(13) A, c = 5.4216(5) A,~ = 95.039(4) 0 ,V = 324.44(5) A.3, Z = 4, and dwc = 5.009 g/cm3• The strongest
X-ray lines (calculated) are 3.512 (100), 3.282 (82), 3.238 (71),2.279 (34), and 4.995 (32). The average of ten microprobe analyses
is 45.15% A~03 and 55.77% Sb20 3, total 100.92, corresponding
to As~,088 Sb0 .9120 3 • Stibioclaudetite forms adamantine, colorlesstransparent bladed crystals to 6 mm, bound by {010} , {110},{111}, and {TOl}. The mineral is flexible with perfect cleavage
on {010}. The hardness is < 2; indices of refraction are > 2.00.
Stibioclaudetite occurs with leiteite, ludlockite, smithsonite andquartz in a vug within massive tennantite from the Tsumeb mine,
Tsumeb, Namibia. Stibioclaudetite is isostructural with claudetite,
specifically an Sb-substituted ordered analog, and the name denotes
the relationship. The crystal structure consists of corrugated sheetsof comer-sharing As0 3 and Sb03 trigonal pyramids arranged in
an ordered, alternating pattern. Raman spectra of stibioclaudetite,claudetite, and leiteite are presented and compared.

The Mineralogical Record, volume 40, May- June, 2009

INTRODUCTION
Mineral dealer David W. Bunk obtained an unusual Tsumeb
specimen containing a well-formed leiteite (ZnAs20 4) blade, redfibrous ludloc.kite, quartz, and an undetermined mineral occurring
as colorless crystals to 6 mm in length. In situ, non-destructive
examination of the unknown mineral with Raman spectroscopy
failed to match its pattern from a large Raman spectral databasethat the Department of Geosciences at the University of Arizona iscurrently constructing. Raman spectroscopy confirmed that three
separate crystals are of the same unknown. Similarities to the Raman
spectrum of leiteite indicated an As3+-bearing structure, and preliminary electron-dispersive spectroscopy (EDS) on an SEM indicatedthe presence of As, Sb and 0 (and no other elements with Z > 8).
Since no known mineral contained only As, Sb and 0, the authors
initiated a full characterization of the material.
Crystal structure determination (Origlieri et al., 2009) andquantitative electron-probe microanalysis identified this phaseas naturally occurring AsSb0 3• Bodenstein et al. ( 1983) studied
synthetic AsSb03 , which they demonstrated to be isostructural
with claudetite (As20 3) (Pertlik, 1978). The crystal structure of this209

Figure 1. The largest cluster of crystals ofstibioclaudetite, 6 mm across, in a vug of massive tennantite with quart.z crystals. This is theholotype specimen. D. W. Bunk specimen, now
in the W. W. Pinch collection.

Figure 2. Scanning electron photomicrographof stibioclaudetite, showing the terminal morphology of the cr ystals.

new mineral consists of corrugated sheets of comer-sharing As0 3
and Sb03 trigonal pyramids, with sheets stacked along [0 10]. The
Commission on New Minerals, Nomenclature and Classification(CNMNC) of the International Mineralogical Association approved
the mineral (proposal IMA2007 -028) and mineral name before
publication. We have deposited type material at the United States
National Museum of Natural History (Smithsonian Institution) in
Washington, D.C. under catalog number 174550. The mineral name,stibioclaudetite, denotes the structural relationship with claudetite,
as an ordered Sb-substituted analog.
Strunz et al. (1958) first reported claudetite from Tsumeb as
gypsum-like platelets. Strunz (1 959) further elaborated, describing
1-3 mm colorless to white crystals with unit cell dimensions a =5.3 A, b = 13.0 A., c = 4.56 A, and~- 94°. He sublimated themineral in a closed glass tube and condensed minute octahedral
crystals. This microchemical behavior is consistent with the known
behavior of claudetite, which condenses into octahedral crystals (i.e.
arsenolite). However, these tests are not sufficient to distinguishclaudetite from stibioclaudetite. Synthetic AsSb03 also has a cubic
modification with the same crystal structure as cubic As20 3 (arsenolite) (Hayek et al., 1963). Consequently, sublimation of either
claudetite or stibioclaudetite would produce octahedral crystals.
The unit cell reported by Strunz (1959) lacks the precision required
to reliably distingu ish stibioclaudetite from claudetite. Keller et al.
( 1979) reported another occurrence of claudetite from Tsumeb inassociation with warikhanite, unfortunately without specifying theidentification method. The original identification of claudetite from
Tsumeb could be in error; therefore Tsumeb specimens labeled"claudetite" warrant re-examination.
Hayek et al. (1963) showed thatcubicAs20 3 (arsenolite) and cubic
Sb20 3 (senarmontite) are miscible, forming a complete solid solution
series. Consequently, ordinary solid solution between arsenolite andsenarmontite might yield cubic AsSb03 without structural orderingof As and Sb atoms. In that case, a cubic ctimorph of stibioclaudetite
would simply be an intermediate of the arsenolite-senarmontite
series, and would not qualify as a new mineral species. The ordering of Sb into a single As position of the claudetite structure isapparently unique to the claudetite and stibioclaudetite structure(Origlieri et al., 2009). A literature search failed to locate any reportof monoclinic Sb2 0 3 ; however, an orthorhombic phase whjch bears
the mineral name valenrinite is well known.
210

Mineralogist Sidney A. Williams identified hexagonal AsSb03
among mine fire products from Nevada (Gibbs, 1985).
OCCURRENCE AND PARAGENESISThe new mineral occurs within a cavity in a massive tennantite
sample (4 X 5 X 7 em) from the Tsumeb mine at Tsumeb, Namibia.
The cavity measures 3 em across, and hosts quartz crystals to
3 mm, a single terminated leiteite blade 7 by 20 mm, red fibersof ludlockite, smithsonite and crystals of stibioclaudetite to 6 mm.
Figure l shows a photograph of the largest group of stibioclaudetite
crystals. Although we do not know the precise original location of
the specimen within the Tsumeb mine, the association with leiteiteleads to certain conclusions. Leiteite occurs in the second and third
oxidation zones at the Tsumeb mine (Gebhard 1991 , 1999). Typeleiteite occurs with tennantite, chalcocite, smithsonite and schneiderhohnite (Cesbron et a/.,.1911). Our present leiteite sample occurs
on tennantite matrix with quartz, ludlockite and smithsonite. This
assemblage suggests that its specific origin within the Tsumeb mine
may be distinct from other known leiteite occurrences.
Although antimony-dominant minerals are not typical of thearsenic-rich assemblages at Tsumeb, primary tennantite contains
substantial antimony (Moritz, 1933). Previous investigators have
The Mineralogical Record, volume 40, May-June, 2009

reported five mineral species from the Tsumeb mine with essential
antimony: famatinite, stibnite, stibiconite and nadorite (Schneider,1992), and biehlite (Schltiter eta/., 2000). Schneider ( 1992) quantifies the 1988 production of NaSb(OH)6 at the Tsumeb smelter at
156 metric tons. Oxidation of host tennantite could readily supply
both the arsenic and antimony sufficient to form stibioclaudetite.
Moritz ( 1933) further notes a substantial zinc content in Tsumeb
tennantite, which could supply both the zinc and arsenic required
to form leiteite (ZnA~04).
Monoclinic As 20 3 (claudetite) forms above 250° C, while cubic
As20 3 (arsenolite) has a melting point near 275° C (Schulman andSchumb, 1943). Hayek et al. (1963) report a melting point of 315° C
for claudetite. In other words, claudetite remains stable at higher
temperatures than arsenolite. Bodenstein et al. (1983) synthesized
their monoclinic AsSb03 at temperatures near 347° C. These dataconservatively bracket the formation of stibioclaudetite between
300° C and 400° C.
Claudetlte
Stlbloclaudetlte

/'

v

v
Figure 3. Crystal morphology of stibioclaudetite,
showing forms {010}, {110}, {111}, and {101}. At
left is claudetite from Imperial County, California, as illustrated by Palache (1934).
APPEARANCE AND PHYSICAL PROPERTIES
Stibioclaudetite forms bladed crystals to 6 mm bound by
major {010}, major {110}, minor {111}, and very rrunor {TO I }.
Stibioclaudetite is colorless and transparent with an adamantine
luster and a white streak. The mineral does not show fluorescence
under ultraviolet radiation. Figure 1 is a close-up of the largest
stibioclaudetite crystals on the holotype, and Figure 2 shows theterminal morphology in a scanning electron micrograph. Figure 3
is a line drawing of the ideal morphology. Stibioclaudetite crystals
mimic the morphology of claudetite from Imperial Valley, California
as illustrated by Palache (1934), shown in Figure 3. Hardness is-2. The mineral has perfect cleavage on {010}, readily obtained.
Cleavage plates are flexible, and deform similarly to gypsum. The
mineral shows strong relief under n= 2.00 index fluids, indicating
an index of refraction above 2.00.
CHEMISTRY
We conducted electron probe microanalysis on a cleavage plateof the stibioclaudetite attached to a glass disc. Qualitative WDS
scans showed only As, Sb and 0, and no other elements with Z > 8.
The Mineralogical Record, volume 40, May-June, 2009

Table 1. Electron probe microanalysis data for stibioclaudetitewith corresponding atomic compositions normalized tothree oxygen atoms. The average of these ten analyses, withstandard deviations is 45.15(0.95)% A~03 , 55.77(1.07)%
Sb10 3, total100.92 %. Normalized to three oxygen atoms, theaverage composition is As 1 .~b0.912 03 • Ideal AsSb03 contains
40.43 % ~0 3 and 59.57% Sb203•% As20 J% Sb20 1

Total

Composition

45.66
44.57
44.82
43.95
44.30
46.62
44.54
46.75
45.50
44.74

55.03
55.46
56.39
55.64
56.13
56.33
56.77
56.76
53.16
56.05

100.69100.02101.22
99.59
100.43102.95101.31103.51
98.67
100.80As l.looSbo.90003
As t.o84S bo.9160 3
As 1.079Sbo.9210 3
As t.076Sbo.92403
As t.o7sSbo.92s0 3
As ..099Sbo.90,03
Ast.onSbo.92s0 3
As, cmSbo9030 3
As, ,,6Sbos840 3
As, 081 Sb0.9,90 J

Standardized quantitative WDS analysis employed a Cameca SX-50
electron microprobe at the Lunar and Planetary Sciences Department, University of Arizona. Operating conditions were 15 kV and
30 nA with a beam diameter of 1.5 Jlffi. Enargite (As) and stibiotantalite (S b) served as standards. Data reduction and correction
followed the PAP method (Pouchou and Pichoir, 1984).
Table l lists the results of ten separate electron probe spot analyses.
The average of these weight percent analyses with standard deviations is: 55.77(1.07)% Sb20 3, 45.15(0.95)% As20 1; total 100.92%.
Normalized to three oxygen atoms, the average composition is
As ..088Sb0.9120 3. The composition remained homogeneous over the
sampled regions. In the solution of the crystal structure, use of theidealized formula AsSb03 produced a smaller residual error than theempirical electron probe formula (Origlieri eta/. , 2009). The crystal
structure analysis indicates that AsSb03more accurately represents
the chemistry of stibioclaudetite than the empirical electron microprobe chemistry given in Table 1. (Origlieri et a/., 2009).
X-RAY CRYSTALLOGRAPHY
We obtained single-crystal X-ray diffraction data using a Bruker
X8 Apex diffractometer equipped with a 4K Apex II CCD detector.
We used monochromatic MoKa radiation generated at 50 kV and 35
rnA. A cleavage fragment of 30 X 70 X 220 Jlffi produced diffraction
spots with streaking along constant 29. Despite the poor appearanceof the data, the reflections yielded a merged Rint value of 3.08%. A
data collection strategy resulted in the acquisition of 1863 framesin 6 scans, from which the Bruker software generated the calculated
powder pattern given in Tabie 2. We used Bruker Saint 7.16b to
fit the unit cell parameters from the positions of 6609 reflections
collected to 82° 29, and Broker Shelxtl 6.14 to determine the spacegroup. Table 3 compares the unit cell parameters for stibioclaudetiteand claudetite (Origlieri et a/., 2009) in Table 3.
RAMAN SPECTROSCOPY
Raman spectroscopy provides a nondestructive and rapid means
to distinguish claudetite from stibioclaudetite. Samples compared
include the stibioclaudetite fragment from our X-ray study; clauderite from Jachymov, Czech Republic (University of Arizona Mineral
Museum 16128; RRUFF R050313); and leiteite from Tsumeb,
Namibia (RRUFF R040011). We collected Raman spectra with abenchtop 100 mW Ar-ion laser centered at 5 14.532 nm and a Jobin
Yvon Spex HR 460 spectometer equipped with a liquid nitrogencooled Princeton Instruments 1152 X 256 pixel CCD detector.
211

Table 2. Calculat ed X-ray powder diffracti on data

Table 3. Compar ison of the unit cells offor stibiocla udetite.

claudeti te and stibiocla udetite.

d

1//0

h

k

l

4.995
3.645
3.512
3.400
3.342
3.282
3.238
3.157
2.80482.80062.70032.65592.64502.27902.26922.24542.14012.1304
2. 1188
2.08532.06461.88251.87201.82231.80961.80501.73441.73051.72701.66491.6574
1.6263
1.6064
1.59321.5702
1.48761.4572
1.3087

32
11
100
18
14
82
71
24
39

0

1

1

-1

1

-1
0
1
0
1

0
1

31
23
28
24
34
8
5
5

9
8
17
13
10
21
8
6
5
16
7
5
7
6

1
1

3
0

0
1
0
1
1
2
1
2
0
2

1

1

3

0
-1

4
3

0

0

I
0
2
-1

-1

3
1
0
2
1
1
5

1

2

2

0

4

2

1
0
2

5

5

1
2

-2
-2
-2

0
4
1

1

7

2

4
0

-1

0
2
1
-1

c
~

v

z

calculated density

Stibioclaudetite

3

-2

17

0

7
7
7

-3
1

4

3

-2

8

1

5.009 g/cm3

4. 174 g/cm3

175

202
210

218
248
259

232
273
298

2
1

138
150
168
179
20 1
205
220
256
269

284

323
342
414
430
468

1

Leiteire

125

193

1
3
3

3
4
8
1

4

Claudetite

171
183

2
0

3

4

155

1

0

5.4216(5) A
95.039(4)0324.44(5) A3

P2rfn
4.5460(4) A
13.0012(14) A
5.3420(5) A
94.329(2) 0314.83(5 ) A3

115
125

0
2

7
6
6

P2/n
4.5757(4) A

stibiocla udetite, claudetit e, and leiteite.

I

2

As20 3

Table 4. Principa l Raman peak positions (shifted cm- 1) of]

3
1

AsSb03*Origlieri et a/. (2009)04

Claudetite*

13.1288(13) A

b

1

4

2
-2

idealized formula
space groupa

Stibioclaudetite

354
356

307
368
379

459

459

541

550
603
649

477
517

620

626
632

631
726
766
8 17

.\

-

I

\......_,..

•

814

764
806

Leiteite-"·--~../

Claudeti teAstibiocla udetite

.)\

100

200

300

400

600

eoo

700

800

aoo

Figure 4. Compar ison of Raman spectra of stibiocla udetite, claudeti te, andleiteite. Table 4lists the peak position sfor these spectra.

Raman Shift (rei. cm-1)

212

The Mineralogical Record, volume 40, May- June, 2009

Using a 1200 grooves rom- • grating centered at 530.4 run and Roper
Instruments Winspec/32 software, we collected the shifted region
from 113 to 1016 em-•.
Figure 4 compares the Raman spectra of stibioclaudetite, clauderite and leiteite, all in undetermined orientations. The stibioclaudetite
spectrum shows 22 vibrational modes. Raman selection rules forthe claudetite and stibioclaudetite structures allow for 15 Ag modes
and 15 B8 modes, not all of which may be visible. Table 4 lists theprincipal Raman peak positions for stibioclaudetite, claudetite andleiteite. Additionally, Raman spectroscopy in the region between
3000-4000 rel em-• showed no active Raman modes of greater
significance than background, demonstrating that the mineral isnominally anhydrous.
ACKNOWLEDGEMENTS
We graciously acknowledge Michael Scott for supporting thecreation of a Raman database of all known mineral species. The
authors appreciate the careful review of Andrew Roberts.
REFERENCES
BODENSTEIN,D.,BREHM,A.,JONES,P.G.,SCHWARZMANN,E.
and SHELDRICK. G. M. (1983) Darstellung und Kristallstruktur
von monoklinem Arsen(Ill)antimon(Ill)oxid, AsSb03 . Zeitschrift
fur Naturforschung, 38B, 901-904.
CESBRON, F. P., ERD, R. C., CZAMANSKI, G. K., and
VACHEY, H. (1977) Leiteite, a new mineral from Tsumeb.
Mineralogical Record, 8(3), Tsumeb! issue, 95- 97.

GEBHARD, G. (1991) Tsumeb: eine deutsch-afrikanische
Geschichte. Verlag Christel Gebhard, Giesen, Germany. 239 pp.
GEBHARD, G. (1999) Tsumeb II. CG Publishing, Waldbrol,
Germany. 328 pp.
GIBBS, R. B. (1985) The White Caps mine, Manhattan, Nevada.
Mineralogical Record, 16, 81-88.
HAYEK, E., INAMA, P., and SCHATZ, B. (1963) MischkristallbiJdung von As20 3 und Sb20 3 . Monatshefte for Chemie, 94,
366-372.

KELLER, P., HESS, H., and DUNN, P. J. (1979) Warikbanit,
Zn3[(H20)2l(As0 4)J, ein neues Mineral aus Tsumeb, Stidwestafrika. Neues Jahrbuchfor Mineralogie Monatshefte, 389-395.
MORITZ, H. (1933) Die sulfidischen Erze der Tsumeb-Mine vonAusgehenden bis zur XVI. Sohle (-460 m). Neues Jahrbuch
for Mineralogie, Geologie, und Paliiontologie, 67A, 118-154,
Tafeln XITI-XIV.
ORIGLIERI, M., DOWNS, R. T., and CARDUCCI, M. D. (2009)
Crystal structures of stibioclaudetite and claudetite. Canadian
Mineralogist (in press).
PALACHE, C. (1934) Contributions to crystallography: claudetite,minasragrite, sarnsonite, native selenium, indium. American
Mineralogist, 19, 194-205.
PERTLIK, F. (1978) Verfeinerung der Kristallstruktur des Minerals
Claudetit, As20 3 ("Claudetit I"). Monatshefte for Chemie, 109,277-282.
POUCHOU, J. L. and PICHOIR, F. (1984) Un nouveau modele
de calcul pour la microanalyse quantitative par spectrometriede rayons X. Partie I: Application a }'analyse d'enchantillons
homogenes. La Recherche Aerospatiale, 3, 167- 192.
SCHNEIDER, G. I. C. (1992) Antimony. In The Mineral Resourcesof Namibia. First Edition. Namibia Geological Survey.
SCHULMAN, J. H. and SCHUMB, W. C. (1943) The polymorphism
of arsenious oxjde. Journal of the American Chemical Society,65, 878- 883.
SCHLUTER, J., KLASKA, K.-H., ADIWIDJAJA, G., FRIESE, K. ,and GEBHARD, G. (2000) Biehlite, (Sb,As)2Mo06, a new mineral from Tsumeb, Namibia. Neues Jahrbuch for Mineralogie,
Monatshefte, 234-240.
STRUNZ, H. (1959) Tsumeb, seine Erze und Sekundarmineralien,insbesondere der neu aufgescblossenen zweiten Oxydationszone.
Forschritte der Mineralogie, 37, 87-90.
STRUNZ, H., SOHNGE, G., and GEIER, B. H. (1958) Stottit, einoeues Germanium-Mineral und seine Paragenese in Tsumeb.
Neues Jahrbuch for Mineralogie Monatshefte, 85-96.
~

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