• journal_title：The Canadian Mineralogist
• Contributor：Pei-Hua Zhang ; Jin-Chu Zhu ; Zhen-Hua Zhao ; Xiang-Ping Gu ; Jin-Fu Lin
• Publisher：Mineralogical Association of Canada
• Date：2004-
• Format：text/html
• Language：en
• Identifier：10.2113/gscanmin.42.3.763
• journal_abbrev：Can Mineral
• issn：0008-4476
• volume：42
• issue：3
• firstpage：763
• section：Articles

Zincospiroffite (Zn₂Te₃O₈), a new tellurite mineral species, was discovered in the Zhongshangou gold deposit in Chongli County, Hebei Province, China. Since it has only been found as crystallite aggregates of hundreds to thousands of micrometers square in a single polished block, most work on the mineral had been carried out under the microscope. This mineral is intimately associated with calaverite and sphalerite, either as micrometric films coating calaverite or in irregular aggregates replacing calaverite. It is a product of secondary co-oxidation of calaverite, associated with sphalerite, pyrite, and other sulfides. It is a gray and translucent mineral, with a dark green streak and a vitreous luster, without internal reflections, and with a weak anisotropy, bireflectance and pleochroism. It is quite soft, has a brittle tenacity and an uneven fracture. Raman spectroscopy demonstrates that the mineral is a natural analogue of synthetic Zn₂Te₃O₈. An electron-microprobe analysis gave the following composition: ZnO 24.57, PbO 1.64, MgO 0.24, TeO₂ 71.90, minor FeO and SeO₂, total 98.89 (in wt.%), corresponding to an empirical formula (Zn_1.97Pb_0.05Mg_0.04Fe_0.02)_{∑ 2.08} (Te_2.95Se_0.01)_∑2.96O_8.00 or, ideally, Zn₂Te₃O₈. Powder X-ray diffraction gave only seven lines with weak intensities [d in Å(I)(hkl): 4.758(w)(110), 3.240(w)(311̅), 2.928(m)(113), 2.820(w)(204̅), 2.155(w)(023,511), 1.985(w)(223), 1.599(w)(425̅), which are similar to those of the synthetic Zn ₂Te₃O₈ (PDF 44–0241). On the basis of the diffraction pattern, the following unit-cell parameters were obtained: a 12.72(4), b 5.15(1), c 11.82(3) (Å), β 99.2(3)°, V 764.57(2.52) ų, with Z = 4 and D_calc = 5.57 g cm⁻³. With these parameters, a comparison is made of zincospiroffite, synthetic Zn₂Te₃O₈ and spiroffite. The new mineral and its name were approved by the Commission on New Mineral and Mineral Names of International Mineralogical Association (IMA 2002–047). The only polished section was housed under catalogue number M10442 in the collection of the Geological Museum of China.