未定名矿物(Bi_(38)CrO_(60))的矿物学研究

Mineragraphy study of Unnamed Mineral(Bi_(38)CrO_(60))

人工合成立方晶体Bi38CrO60在自然界首次发现于中国陕西省洛南县驾鹿金矿床中,暂称之为未定名矿物。其共生和伴生矿物有黄铁矿、自然金、碲金矿、含氧金矿物等。常呈不规则粒状集合体,偶见立方体微晶(粒径小于0 05mm),棕黑色,金属光泽;HV=232 78kg/mm2,HM=4 15;D=14 10(3)g/cm3,Dx=14 08(2)g/cm3,n=3 14(3)。EPM8100探针分析Bi2O3为98 854%、CrO3为1 111%,合计99 965%,化学式为Bi38 009Cr0 995O60;CAMEBAX-SX51探针分析Bi2O3为98 862%,CrO3为1 112%,合计99 974%,化学式为Bi38 008Cr0 996O60。均可写为Bi38CrO60。X射线粉晶分析主要强度线d(I)(hkl)分别为0 3215(100),(310);0 27211(72),(321);0 17145(40),(530);0 1696(30),(600);0 1651(30),(611);0 1608(30),(620);0 29411(25),(222);0 3596(22),(220);0 2171(20),(332);0 1503(20),(631),等轴晶系,可能的空间群为Im3m;a=1 0181(1)nm,c/a=1,晶胞体积v=1 05529(1)nm3,z=1。1-Kp/Kc=0 019。Cr6+,Bi3+,O2-。未定名矿物和人工晶体的化学成分与X射线粉晶数据基本一致。

Bi_(38)CrO_(60):The artificial square crystal was first discovered in nature at Jialu gold deposit in Luonan County of Shaanxi province. Temporarily, people called it Unnamed Mineral. It is closely associated with pyrite, nature gold, calaverite, oxygen-bearing gold minera et al and appeared as irregular grained aggregates, the cubic crystals(<0.05 mm) are rare, brownish black, metals luster; H_V=232.78 kg/mm^2,H_M=4.15; D=14.10(3) g/cm^3,D_x=14.08(2) g/cm^3; n=3.14(3). The microprobe analysis are:in EPM8100,Bi_2O_3 is 98.854%, CrO_3 is 1.111%, total is 99.965%; the chemistry type is Bi_(38.009)Cr_(0.995)O_(60); in CAMEBAXSXS51,Bi_2O_3 is 98.862%, CrO_3 is 1.112%, total is 99.974%,the chemistry type is Bi_(38.008)Cr_(0.996)O_(60). Both can been write as Bi_(38)CrO_(60); the main strong line d(I)(hkl) in X-ray crystallography analysis is 0.321 5(100),(310); 0.272 11(72),(321); 0.171 45(40),(530); 0.169 6(30),(600); 0.165 1(30),(611); 0.160 8(30),(620); 0.294 11(25),(222); 0.359 6(22),(220); 0.217 1(20),(322); 0.150 3(20),(631) respectively; isometric system,the possible space cluster is Im3m;a=1.018 1(1)nm,c/a=1, crystal volume v=1.055 29(1) nm^3,z=1,1-K_p/K_c=0.019.Cr^(6+),Bi^(3+),O^(2-). The composition and X-ray crysytal quantity of Unnamed Mineral and artificial crystal (Bi_(38)CrO_(60)) are consistence.