Lisiguangite,CuPtBiS_3,is a new mineral species discovered in a PEG-bearing,Co-Cu sulfide vein in garnet pyroxenite of the Yanshan Mountains,Chengde Prefecture,Hebei Province, China.It is associated with chalcopyrite and bornite,galena,minor pyrite,carrolite,molybdenite and the platinum-group minerals daomanite(CuPtAsS_2),Co-bearing malanite(Cu(Pt,Co)_2S_4)sperrylite, moncheite,cooperite and malyshevite(CuPdBiS_3),rare damiaoite(Pt_2In_3)and yixunite(Pt_3In). Lisiguangite occurs as idiomorphic crystals,tabular or lamellae(010)and elongated[100]or as aggregates,up to 2 mm long and 0.5 mm wide.The mineral is opaque,has lead-gray color,black streak and metallic luster.The mineral is non-fluorescent.The observed morphology displays the following forms:pinacoids{100},{010},{001},and prism{110}.No twining is observed.The a:b:c ratio,calculated from unit-cell parameters,is 0.6010:1:0.3836.Cleavage:{010}perfect,{001}distinct, {100}may be visible.H Mohs:2 1/2;VHN_(25)=46.7-49.8(mean 48.3)kg/mm^2.Tenacity:brittle. Lisiguangite is bright white with a yellowish tint.In reflected light it shows neither internal reflections nor bireflectance or pleochroism.It has weak to moderate anisotropy(blue-greenish to brownish)and parallel-axial extinction.The reflectance values in air(and in oil)for R_3,R_4 and(^(im)R_3,^(im)R_4),at the standard Commission on Ore Mineralogy wavelengths are:37.5,35.7(23.4,22.3)at 470 nm;38.6,36.5 (23.6,22.6)at 546 nm;39.4,37.5(23.6,22.7)at 589 nm and 40.3,38.2(23.7,22.9)at 650 nm.The average of eight electron-microprobe analyses:Cu 12.98,Pt 30.04,Pd 2.69,Bi 37.65 and S 17.55, totaling 100.91%,corresponding to Cu_(1.10)(Pt_(0.83),Pd_(0.14))_(Σ0.97)Bi_(0.97)S_(2.96)based on six atoms apfu.The ideal formula is CuPtBiS_3.The mineral is orthorhombic.Space group:P2_12_12_1,a=7.7152(15),b=12.838(3) ,c=4.9248(10),V=487.80(17)~3,Z=4.The six strongest lines in the X-ray powder-diffraction pattern[d in(I)(h k l)are 6.40(30)(020),3.24(80)(031),3.03(100)(201),2.27(40)(051),2.14(50)(250), 1.865(60)(232).
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