新矿物伊逊矿——有序的铂与铟的天然合金

YIXUNITE——AN ORDERED NEW NATIVE INDIUM AND PLATINUM ALLOY

伊逊矿产在石榴石角闪石辉石岩的含钴、铜的铂矿脉中,常呈直径为1.0—2.0mm的小圆球,与大庙矿紧密连晶。伊逊矿为不透明,金属光泽;颜色钢灰色.条痕黑色;莫氏硬度H_M=5.8,显微硬度VHN_(50)=634kg/mm^2;均质性,无解理;计算密度D_(calc.)=18.219/cm^2。8个电子探针分析的平均化学成分(％)为:Pt 82.8(81.8—83.6)、In 16.4(l5.6—17.1)。化学式为:Pt_3In。5条最强X射线衍射线(hkl,d,I)为:111,2.30(100);200,1.99(60);202,1.411(40);311,1.203(80);222,1.151(40)。X射线粉晶衍射线指标化后,求得该矿物为等轴晶系。空间群:Pm3m。α=0.3988(3)nm,V=0.06343nm^3,Z=1。

Yixunite was found in a cobalt-, copper-bearing platinum vein in garnet-amphibole pyroxen-ite(a contact zone of pyroxenite with granite), which is situated near the Yixun River. The chief ore minerals are bornite, chalcopyrite, magnetite and carrolite. Yixunite occurs as immiscible globules 1. 0-2. 0 mm in diameter (product of complexing in hydrothermal solution). It is associated with moncheite, sperrylite, cobalt malanite and cooperite in chalcopyrite. Yixunite was also obtained from heavy concentrates of crushed ores. It occurs either as single globules or is intimately associated with damiaoite (PtIn2), situated in the inner part of a globule. Opaque with metallic luster. Colour bright white with a black streak. Hu5. 8. VHN50 = 634 kg/mm2 (range 573-681 kg/mm2). Insoluble in HCl, HNO3, HF and H3PO4 Cleavage none. Magnetic none. Density could not be measured because of the small grain size. Density (calc. ) = 18. 21 g/cm3. Reflective colour is bright white with a yellowish tint. Isotropic. The bireflectance and pleochro-ism in air not observed. Relfectance values were measured in air by using WTIC as the standard. Eight chemical analyses were carried out by means of an electron microprobe using following standards; pure metals Pt La and In La. The mean analytical results (and ranges) (% ) are: Pt 82. 8 (81. 8-83. 6), In 16. 4 (15. 6-17. 1) .and total 99. 2. The empirical formula (based on 4 atoms) is: Pt2.993In 1.007. The X-ray powder diffraction was studied with Mn-filtered Fe radiation by a 57. 3 mm diameter Debye camera. Yixunite could be indexed on a cubic unit cell with a space group Pm3m. After refinement from the powder data we obtained: a=0. 3988 (3) nm, Z = 1. It is named after its locality which is situated near the Yixun River, about 270 km N of Bei-jing