The Crystal Chemistry and Crystal Structure of Kuksite, Pb3zn3te6+
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American Mineralogist, Volume 95, pages 933–938, 2010 6+ The crystal chemistry and crystal structure of kuksite, Pb3Zn3Te P2O14, and a note on the crystal structure of yafsoanite, (Ca,Pb)3Zn(TeO6)2 STUART J. MILL S ,1,* ANTHONY R. KA M PF ,2 UWE KOLIT S CH ,3,4 ROBERT M. HOU S LEY,5 AND MATI RAUD S EPP 1 1Department of Earth and Ocean Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada 2Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, U.S.A 3Mineralogisch-Petrographische Abt., Naturhistorisches Museum, Burgring 7, A-1010 Wien, Austria 4Institut für Mineralogie und Kristallographie, Geozentrum, Universität Wien, Althanstrasse 14, A-1090 Wien, Austria 5Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, U.S.A. AB S TRACT 6+ New discoveries of kuksite, Pb3Zn3Te P2O14, from the Black Pine mine, Montana, and Blue Bell claims, California, have enabled a detailed crystal-chemical study of the mineral to be undertaken. Single-crystal X-ray structure refinements of the structure indicate that it is isostructural with dugganite, 6+ 5+ 6+ Pb3Zn3Te As2O14, and joëlbruggerite, Pb3Zn3(Sb ,Te )As2O13(OH,O). Kuksite from the Black Pine mine crystallizes in space group P321, with unit-cell dimensions a = 8.392(1), c = 5.204(1) Å, V = 3 317.39(8) Å , and Z = 1 (R1 = 2.91% for 588 reflections [Fo > 4σF] and 3.27% for all 624 reflections), 3 while Blue Bell kuksite has the unit cell a = 8.3942(5), c = 5.1847(4) Å, and V = 316.38(4) Å (R1 = 3.33% for 443 reflections [Fo > 4σF] and 3.73% for all 483 reflections). Chemical analyses indicate that solid-solution series exist between kuksite, dugganite, and joëlbruggerite. Raman spectroscopic and powder X-ray diffraction data are also presented for samples from both occurrences. 6+ The crystal structure of the chemically related species yafsoanite, (Ca,Pb)3Te2 Zn3O12, from the type locality (Delbe orebody, Kuranakh Au Deposit, Aldan Shield, Saha Republic, Russia), has been refined to R1 = 2.41% for 135 reflections [Fo > 4σF] and 3.68% for all 193 reflections. A garnet-type structure has been confirmed and significantly improves upon the results of an earlier structure determination. Keywords: Kuksite, dugganite, joëlbruggerite, Black Pine, Blue Bell, tellurate, yafsoanite, Delbe orebody, crystal structure INTRODUCTION Kuksite occurs with malachite, pseudomalachite, chalcocite, Tellurium minerals occur in a wide range of environments tetrahedrite, segnitite, dugganite, and joëlbruggerite in milky worldwide, where primary sulfides and sulfosalts have undergone quartz veins. Kuksite crystallized from solutions rich in Pb, Zn, weathering under acidic conditions. Tellurium mineralogy tends to Sb, As, P, and Te derived from the breakdown of the primary be complex, owing to the various oxidation states possible (Te6+, ore body within the Mount Shields Formation (Peacor et al. Te4+, Te0, and Te2–), which then tend to combine to create many 1985; Mills et al. 2009). The tellurium is present in the ore as a exotic mineral species. Investigations of tellurium mineralogy at substituent in tetrahedrite, a common association in many other the Black Pine mine, 14.5 km NW of Philipsburg, Granite County, deposits (e.g., Fadda et al. 2005). Thermodynamic modeling Montana [U.S.A. (46°26′52″N, 113°21′56″W)], and the Blue suggests that kuksite formed in mildly oxidizing [log aO2(aq) Bell claims, Baker, San Bernardino County, California [U.S.A. > –41] and acidic conditions (pH < 3), as required for other (35°14′38″N, 116°12′25″W)], resulted in the discovery of several unique Black Pine minerals such as joëlbruggerite (Mills et al. rare and new tellurate species. One of these rare tellurates, kuksite, 2009) and auriacusite (Mills et al. 2010). Synthetic analogues of 6+ kuksite can be prepared at >500 °C by solid-state methods (Mill’ Pb3Zn3Te P2O14, is the subject of this report. Kuksite is an extremely rare mineral that previously has only 2009a, 2009b); however, natural samples have almost certainly been described from its type locality, the Delbe orebody within the crystallized at ambient (~25 °C) temperatures. Kuranakh Au Deposit, Aldan Shield, Saha Republic, Russia (Kim et al. 1990). Here it occurs as elongated tabular gray crystals up to Blue Bell claims 0.1 × 0.3 mm with cinnabar, gold, petzite, coloradoite, yafsoanite, Although the Blue Bell mine has been a well-known collect- kuranakhite, cheremnykhite, descloizite, dugganite, and saponite. ing locality for micro minerals at least since 1977 (Crowley 1977) and 45 minerals from there were described in detail by Maynard OCCURRENCE AND PARAGENE S I S (1984), the first tellurate mineral described from the mine, Black Pine mine quetzalcoatlite, was collected by one of the authors (R.M.H.) Kuksite and associated material was collected in the spring of in March of 1996. Shortly following news of this find, kuksite 1993 by John Dagenais of Vancouver, British Columbia, Canada. was found in a single Blue Bell specimen submitted to R.M.H. by Eugene Reynolds. These finds were promptly documented * E-mail: [email protected] in a regional publication (Housley 1997), although the quetzal- 0003-004X/10/0007–933$05.00/DOI: 10.2138/am.2010.3483 933 934 MILLS ET AL.: KUKSITE AND YAFSOANITE coatlite was initially misidentified as tlalocite. Subsequently, Zn), Cu-metal (for Cu), fayalite (for Fe), Te-metal (for Te), Sb- a crystal of the quetzalcoatlite was used to solve the structure metal (for Sb), fluorapatite (for P), GaAs (for As), and anorthite of that mineral (Burns 2000). What is now known as the Blue (for Si). Like many other tellurium oxysalts and dugganite-group Bell claims actually consists of a dozen or more small workings members, kuksite is prone to beam damage (including melting distributed over a rugged hillside. observed under stronger analytical conditions) and anomalously In 2007, R.M.H. found kuksite in material from the Blue low totals (Table 1), cf. Grundler et al. (2008), Mills et al. (2009), Bell D site (Maynard 1984) that had been donated for study by and Kampf et al. (2010). John Jenkins. In March 2008, R.M.H. finally found kuksite in The average of five analyses (calculated on the basis of 14 situ in a small adit at the D site. Ironically, somewhat earlier in O) gave the average composition of Pb2.93(Zn2.74Cu0.06Fe0.01)Σ2.81 November 2007, Brent Thorne had independently found larger (Te0.58Sb0.33)Σ0.91(P1.44As0.74Si0.11)Σ2.29O14 for Black Pine kuksite, kuksite crystals associated with quetzalcoatlite in the D site shaft, while the average of seven analyses gave the average compo- where quetzalcoatlite had been initially found. He kindly made sition of (Pb2.89Bi0.10)Σ2.99(Zn2.84Cu0.20Fe0.02)Σ3.05Te1.05(P1.52Si0.44 some of these crystals available for this study in June 2008. As0.02)Σ1.98O14 for Blue Bell kuksite. The Black Pine kuksite con- At the Blue Bell the most ubiquitous associates of kuksite are tains substantial As, indicating a solid solution toward dugganite, clinochlore, perite, and hemimorphite. Other secondary minerals but also contains substantial Sb toward what would be the Sb found in close association include hematite, quartz, wulfenite, analog of kuskite. We note that semi-quantitative SEM analyses chlorargyrite, dioptase, kettnerite, fluorite, murdochite, and very show Sb to be low or absent in many samples, indicating multiple minor calcite, barite, and gypsum. Many chrysocolla pseudo- generations of formation and/or differing primary minerals to be morphs apparently, at least partly, after aurichalcite are also pres- responsible for formation. Varying Sb is also present in auriacus- ent, as is much gossan. Interestingly, much more Te mineralization ite and alunite supergroup minerals from Black Pine. The Blue is present at this site as green and yellow, X-ray amorphous, Bell kuksite, on the other hand, shows substantial Si substitution opal-like gels consisting of Zn, Cu, Bi, Te, Fe, and Si oxides than analogous to that reported by Kim et al. (1988). the small amount found in well-crystallized minerals. This part of the Blue Bell claims is located in a skarn area, Raman spectroscopy and although the area appears to be highly oxidized, some small Near-infrared Raman spectroscopic analysis was performed inclusions of primary minerals are trapped in garnet and mag- using a Renishaw imaging microscope system 1000 (Depart- netite of the skarn. These inclusions include sphalerite, bornite, hessite, and tetradymite. Thus, it appears that the suite of sec- ondary minerals including the kuksite could have formed during oxidation of the primary minerals present, with perhaps only Mo and P needing to be derived from the surrounding skarn. PHY S ICAL PROPERTIE S Black Pine mine Kuksite commonly occurs in various shades of purple, as barrel-shaped or tabular crystals up to about 0.5 mm across (Fig. 1). Forms observed are {0001}, {1120}, {1010}, and {1121}. The barrel-shaped crystals can be randomly color-zoned, with purple, grayish purple, and colorless most prominent. Less com- monly, kuksite may occur as bluish or greenish crystals. Visually, kuksite is indistinguishable from the related species dugganite, 6+ 5+ 6+ Pb3Zn3Te As2O14, and joëlbruggerite, Pb3Zn3(Sb ,Te )As2O13 (OH,O), although joëlbruggerite tends to be an order of magni- FIGURE 1. Barrel-shaped crystal of kuksite from the Black Pine mine tude smaller than both kuksite and dugganite. in quartz vugh. Field of view is 0.3 mm across. Jean-Marc Johannet specimen and photograph. Blue Bell claims TABLE 1. Quantitative chemical analyses for kuksite (average of five Kuksite occurs as pale greenish-blue simple stout hexagonal analyses for Black Pine and seven for Blue Bell) prisms up to about 0.1 mm in length.