四方铜金矿CuAu在我国发现

四方铜金矿产于新疆玛纳斯县清水河上游萨尔达拉含铂基性-超基性岩体中。岩体主要为暗绿色蛇纹石化斜辉辉橄岩,岩石化学成分多数为正常系列,少数为铝过饱和系列。岩体长9公里,宽140米,是一个向南倾斜的单斜岩墙。岩体侵入到泥盆系头苏泉组的黑灰色粉砂质板岩中。外接触带仅几十厘米到1米左右宽,以绿泥石化、绿帘石化、蛇纹石化为主,其次是碳酸岩化。内接触带有1米多宽,以蛇纹石化、透辉石化、透闪石化为主,个别地段有阳起石、透闪石软玉。

TETRAAURICUPRIDE,CuAu DISCOVERED IN CHINA

Electron probe quantitative analysis of tetraauricupride with sterling elements Cu,Au as standards (wt%),gives Cu 23.74 (%).Au 75.81 (%).The empirical formula is (Cu_o.3736 Au_o.3817).The ideal formu’a is CuAu.The mineral belongs to tetragonal system with a₀=3.89 (Å),c₀=3.72 (Å),z=2.Space group is D_4h¹=C4/mmm.There are two molecules in a unit cell,with its theoretical specific gravity (by Cu:Au=1:1) D_x=14.67.The strongest lines of X-ray powder diffraction pattern are (in Å) : 2.24 (10) (111),1.99 (5) (020),1.55 (4) (112),1.36 (4) (202),1.195 (10) (131),1.25 (doublets (6) (113,222),1.040 (doublets) (5) (207,312).The mineral grain is irregular,600×350×50μm.Its hardness is VHN₂₀=294,equivalent to the Moh’s hardness 1.6.The new mineral is weak anisotropic,with spectral reflectivities,as follows (σ,R%) : 405 nm 44.6,436 nm 46.8,480 nm 50.3,526 nm 55.8,546 nm 61.2,578 nm 74.4,589 nm 76.6,622 nm 83.6,644 nm 84.9,656 nm 85.4,664 nm 86.6,and 700 nm 97.3.Color copped red,with a yellow tint.Strong metallic luster.The mineral doesn’t dissolve in hydrochloric-,sulphuric-and nitric acid.Tetraauicupride was found in a platinum-bearing basic-ultrabasic stock at Sardala,Manas County,Xinjiang Autonomous region.Associated minerals are diopside,tremolite,apatite,zircon,mangetite,chromite,pyrrhotite,pyrite,chalcopyrite,gold,silver and platinum group minerals.The mineral is named after its symmetry and chemical composition.The type specimens are kept in the Geological Museum of the Ministry of Geology in Beijing.Discussion (by the authors):1.The tetragonal C-face-centred lattice is taken for comparing with the structures of gold,copper.The space group and cell parameters of the new mineral can be converted into tetragonal system,space group D_4h¹=P4/mmm,with a₀=2.815 (Å),C₀=3.720 (Å),z=1.2.Auricuperide,CuAu,tetragonal,a,c=2.81,3.72 (Å),z=1.It was known only in Klockmann’s Lehrbuch der Mineralogie (1978,p 395).The unnamed mineraloccurred in Hortonolithdunit,Sud-Afrika.