邛莫金矿床中块硫锑铜矿含硒性及其特征

硒的块硫锑铜矿产于西秦岭邛莫金矿床中,与其伴生的矿物有硒汞矿、硒铅矿、硒锑矿、斜方硒镍矿、硒铜镍矿、硒质辉锑矿、自然金以及石英、重晶石等。 含硒的块硫锑铜矿平均显微硬度VHN50=247.5kg/mm2,相当于摩氏硬度4.2。电子探 针分析结果(w,％)为：Sb 25.79,Cu 38.20,S 21.12,Se 1 2.76,Hg 0.0 0～1.49(平均0.58),Ag 0.00～0.33(平均0.09),As 0.00～2.01(平均0.76)。根据成分中S e/(S+Se)比值(原子比)＜0.2抑≥0.2,可将所测矿物划分为含硒质块硫锑铜矿与硒质块硫锑 铜矿。它们的化学分子式分别为: (Cu2.84Hg0.01)2.85(Sb1.00A s0.07)1.07(S3.54Se0.46) 4.00和(Cu3.05Hg0.03)3.08(Sb1.07As0.03) 1.10(S2.77Se1.23)4.00。代表性的反射率(％): (470nm) Rγ'=22.84～22.50, Rα'= 27.92～27.99; (550 nm) Rγ'= 22.63～22.76, Rα'=2 7. 79～28.11; (590nm) Rγ'=22.92～22.08, R α'=28.27～28. 72; (650nm) Rγ'=23.08～23.76, Rα'=28.79～29.13。

Selenium Concentration and Characteristics of Famatinite from Qiongmo Gold Deposit, Western Qinling Mountains

The Qiongmo gold deposit occurs in the Cambrian silicalite and slate in the sou th subzone of western Qinling Mountains. The Se-bearing and selenium famatinite are found in quartz-barite veins in the form of dissemination or veinlets. The associated minerals include tiemannite, clasthalite, antimonselite, kullerudi te, penroseite, selenium stibnite, native gold, barite and quartz. The mineral is lead-gray in colour, brashy, with metallic luster, and 0.01～0.1mm in size. The average microhardness is 247.5kg/mm2 (for 50g load) corresponing to Moh s' hardness=4.2. The reflectance values (SiC standard) are given in 10nm steps. The representative R values are: (470nm), Rγ'=22.84～22.50, Rα'= 27.92～27 .99; (550nm), Rγ'= 22.63～22.76, Rα'=27.79～28.11; (590nm), Rγ'=22. 92～ 22.08, Rα'=28.27～28.72; (650nm), Rγ'=23.08～23.76, Rα'=28.79～29.13. E lectron microprobe analyses of eleven points on famatinite gave the results as f ollows (wt％): Sb, 24.42～28.12 (25.79 in average ); Cu, 36.60～39.94 (38.2 0 in average);S, 14.49～25.74 (21.12 in average);Se, 6.11～23.89 (12.76 in average ). Based on Se/(S+Se) ratios of microprobe analyses the mineral is classified as Se-bearing famatinite and selenium famatinite, corresponding to the formula (C u2.84Hg0.01)2.85(Sb1.00As0.07)1.07(S3.54 Se0.46)4.00 and (Cu3.05Hg0.03)3.08(Sb1.07A s0.03)1.10(S2.77Se1.23)4.00 respectively.