砷铜矾的发现与研究

砷铜矾（Ｐａｍａｕｉｔｅ）在１９７８年首次发现于美国，１９８４年笔者在广西德保矿区也发现了这种矿物，笔者发现在这种矿物有两种形态，即纤维状和薄片状。纤维状砷铜矾的化学成分为（％）：ＣｕＯ５８．６９，Ａｓ２Ｏ５１７．４１，ＳＯ３６．５４，ＦｅＯ０．８６，ＳｉＯ２０．０８，（Ｈ２Ｏ１７．７０），其理想分子式为：Ｃｕ９（ＡｓＯ４）２（ＳＯ４）（ＯＨ）１０．７Ｈ２Ｏ，与美国产出的砷铜矾的化学成分基本一致，

Discovery and Study of Parnauite

Parnauite was first discovered in the United States in 1978. In China, it was first found in the Debao ore district of Guangxi in 1984. There are two forms of parnauite in Debao: foliated and fibrous. Chemical compositionof the foliated parnauite is given as follows (in percentage): CuO 56. 09, As2O518. 39, Al2O30. 21, FeO 0. 40, SiO20. 56, SO35. 20, CO23. 83, H2O+14. 40, totally 99. 08, suggestingan ideal chemical formula of Cu9(AsO4)2(SO4) (CO3) (OH)8·6H2O, which is somewhat different from that of parnauite fromtheUnitedStates; nevertheless, the compositionof the fibrousparnauite issimilar to that of parnauite from the United States. The foliated parnauite is jade green to greyish in color, and transparent, glassy to pearly in luster.H=2,Dm=3. 33,Dc=3. 35, biaxial negative. Refractive indicesNp=1. 709,Nm=1. 732,Ng=1. 738; 2V=54. 63°. The strongest lines in X-ray diffraction pattern of the foliated parnauite are 14. 85 (100), 10. 45 (15), 7. 20 (10), 6. 46 (12),4. 55 (60), 4. 03 (20), 2. 867 (17), 2. 818 (10). Orthorhombic system, space groupP2122, cell dimensionsa=14. 92°A,b=14. 28°A,c=6. 02°A, calculated cell dimensionsa=15. 052 (18)°A,b=14. 320 (7)°A,c=6. 002 (6)°A,Z=2.