Xitieshanite——A New Ferric Sulphate Mineral

【摘要】 <正> Xitieshanite is a new ferric sulfate mineral discovered in the oxidation zone of a Pb-Zndeposit at Xitieshan,Qinghai Province,China.The typical crystal of xitieshanite is a rhom-bic rectangle.It is bright green in colour with a light yellow tint.Luster vitrous Translu-cent to almost transparent.Streak yellow.Cleavage imperfect.Fracture uneven or conchoi-dal.H.（Vickers）=62.6kg/mm².Specific gravity=1.99_obs.(2.02_calc,).Pleochroism strong,andaxial colours:X=colourless to pale yellow,Y=pale yellow,Z=light yellow with greenishtint..It is optically positive,biaxial,2V=77°,r v.Refractive indices:N_x=1.536,N_y=1.570,N_z=1.628.Extinction parallel and inclined.Elongation positive and negative.X-raysingle-crystal study shows it is monoclinic.Space group P2₁/a.Unit cell parameters:a=14.102,b=6.908,c=10.673（?）,β=111.266°,V=968.9,（?）³,Z=4.The powder pattern of xitie-shanite gave the strongest lines:6.67（6）（201）,6.09（5）（110）,5.69（5）（011）,4.96（10）（002）,4.81（10）（211）,4.21（5）（112）,and 3.90（9）（211）.Chemical analysis gave Al₂O₃ 0.01,Fe₂O₃26.15,FeO 0.18,MgO 0.03,CaO 0.09,K₂O 0.03,Na₂O 0.07,SO₃ 27.69,H₂O 45.02,total 99.27%,corresponding to the chemical formula:Fe³⁺ （SO₄）（OH）·7H₂O.The DTAcurve shows respectively three strong endothermic peaks at 85°,170°,and 735℃,anda weak peak at 460℃.The TGA curve shows a loss of weight in three different steps.The infrared spectral curve of xitieshanite demonstrates that it has two principal absorptionbands at 3,350 and 1,225—1,003 cm^-1 and two subordinate bands at 1,620 and 603 cm^-1.更多还原

【Abstract】 Xitieshanite is a new ferric sulfate mineral discovered in the oxidation zone of a Pb-Zn deposit at Xitieshan,Qinghai Province,China.The typical crystal of xitieshanite is a rhom- bic rectangle.It is bright green in colour with a light yellow tint.Luster vitrous Translu- cent to almost transparent.Streak yellow.Cleavage imperfect.Fracture uneven or conchoi- dal.H.（Vickers）=62.6kg/mm².Specific gravity=1.99_obs.(2.02_calc,).Pleochroism strong,and axial colours:X=colourless to pale yellow,Y=pale yellow,Z=light yellow with greenish tint..It is optically positive,biaxial,2V=77°,r v.Refractive indices:N_x=1.536,N_y= 1.570,N_z=1.628.Extinction parallel and inclined.Elongation positive and negative.X-ray single-crystal study shows it is monoclinic.Space group P2₁/a.Unit cell parameters:a= 14.102,b=6.908,c=10.673（?）,β=111.266°,V=968.9,（?）³,Z=4.The powder pattern of xitie- shanite gave the strongest lines:6.67（6）（201）,6.09（5）（110）,5.69（5）（011）,4.96（10）（002）, 4.81（10）（211）,4.21（5）（112）,and 3.90（9）（211）.Chemical analysis gave Al₂O₃ 0.01,Fe₂O₃ 26.15,FeO 0.18,MgO 0.03,CaO 0.09,K₂O 0.03,Na₂O 0.07,SO₃ 27.69,H₂O 45.02, total 99.27%,corresponding to the chemical formula:Fe³⁺ （SO₄）（OH）·7H₂O.The DTA curve shows respectively three strong endothermic peaks at 85°,170°,and 735℃,and a weak peak at 460℃.The TGA curve shows a loss of weight in three different steps. The infrared spectral curve of xitieshanite demonstrates that it has two principal absorption bands at 3,350 and 1,225—1,003 cm^-1 and two subordinate bands at 1,620 and 603 cm^-1.更多还原