Verbeekite, monoclinic PdSe ₂ , a new mineral from the Musonoi Cu-Co-Mn-U mine, near Kolwezi, Shaba Province, Democratic Republic of Congo (original) (raw)

none 10.1180/0026461026610020 Mineralogical Society The Mineralogical Society 7149 4693311 5840 2021020409165188961 10.1180 2021-02-04T14:43:31Z 2002-07-27T12:35:26Z 15 Mineralogical Magazine Mineral. mag. 0026-461X 1471-8022 02 2002 66 1 Verbeekite, monoclinic PdSe ₂ , a new mineral from the Musonoi Cu-Co-Mn-U mine, near Kolwezi, Shaba Province, Democratic Republic of Congo A. C. Roberts W. H. Paar M. A. Cooper D. Topa A. J. Criddle J. Jedwab Abstract Verbeekite, ideally PdSe2 , monoclinic with space-group choicesC 2/m ,C 2 orC m ;a = 6.659(7),b = 4.124(5),c = 4.438(6) Å, ß = 92.76(3)°,V = 121.7(4) Å3 ;a :b :c = 1.6147:1:1.0761, Z = 2, is a new, very rare, primary mineral, intimately associated with secondary oosterboschite {(Pd,Cu)7 Se5 }, from the Musonoi Cu-Co-Mn-U mine, near Kolwezi, Shaba Province, Democratic Republic of Congo. Additional associated minerals are Cu- and Pd-bearing trogtalite {(Co,Cu,Pd)Se2 }, Se-bearing digenite and Se-bearing covellite. The strongest five lines of the X-ray powder-diffraction pattern {d in Å (I ) (hkl )} are: 4.423(30)(001), 3.496 (30)(110), 2.718(100)(111), 1.955(50)(310 and 1.896(50)( 12). The mineral has also been identified, as a single anhedral 25 µm-sized grain, from Hope's Nose, Torquay, Devon, England where it is associated with native gold, chrisstanleyite Ag2 Pd3 Se4 , oosterboschite(?), unnamed Pd2 HgSe3 and cerussite. At Musonoi, altered verbeekite grains do not exceed 200 µm in size and are anhedral, black, with a black streak and a metallic lustre. The mineral is opaque, brittle, has an uneven fracture, and lacks discernible cleavage. The VHN5 ranges 490–610, mean 550 kp/mm2 (2 indentations), roughly approximating a Mohs' hardness of 5Ý.D calc. = 7.211 g/cm3 for the ideal formula. Electron-microprobe analyses (mean of 4 spot analyses) yielded Pd 39.6, Cu 0.5, Se 58.8, total 98.9 wt.%. The empirical formula is (Pd0.99 Cu0.02 )σ1.01 Se1.99 , based on Pd+Cu+Se = 3. In plane-polarized reflected light, the mineral is a nondescript grey and is neither pleochroic nor perceptibly bireflectant. Anisotropy is moderate with rotation tints in varying shades of brown. Reflectance spectra and colour values are tabulated. The name honours Dr Théodore Verbeek (1927–1991) who was the first geoscientist to study the Musonoi palladium mineralization in the Democratic Republic of Congo (1955–1967) and who co-discovered this new mineral phase. 07 05 2018 02 2002 173 179 S0026461X00045060 https://www.cambridge.org/core/terms 10.1180/0026461026610020 https://www.cambridge.org/core/product/identifier/S0026461X00045060/type/journal\_article https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0026461X00045060 http://minmag.geoscienceworld.org/cgi/doi/10.1180/0026461026610020 10.1107/S0365110X57000948 10.3406/bulmi.1969.6357 The Canadian Mineralogist IMA/COM Report on Symbols and Definitions 18 549 1980 Henry François, A. (1987) Synthse géologique sur l'Arc cuprifre du Shaba (Rép. du Zaïre). Societé Belge de Géologie, Vol. hors-série. Centenaire 1987, 15–64. Centenaire des premiéres études sur la géologie shabienne (Zaï): Gisements de cuivre stratiformes et minéralisations associée. 325 1997 Jedwab 10.3406/bulmi.1971.6619 Mineralogical Record Famous mineral localities: The uranium deposits of the Shaba Region, Zaïre 20 265 1989 Gauthier Stratiform Copper Deposits in Africa Part 2 – Tectonics. 47 1963 Demesmaeker 10.3406/bulmi.1965.5815 10.1180/002646198547611 10.3406/bulmi.1970.6496 10.3406/bulmi.1965.5874 The Canadian Mineralogist Editorial policy for the second issue of the IMA/COM Quantitative Data File 18 553 1980 Criddle Stratiform Copper Deposits in Africa, Part 1 – Lithology, Sedimentology. 71 1962 Oosterbosch