Muchuanite, a new water-bearing molybdenum sulphide mineral, was discovered in aseries of molybdenum-bearing feldspathic quartz-sandstone of the Jurassic system,Sichuan Province, China. Muchuanite is darkly powdery an...Muchuanite, a new water-bearing molybdenum sulphide mineral, was discovered in aseries of molybdenum-bearing feldspathic quartz-sandstone of the Jurassic system,Sichuan Province, China. Muchuanite is darkly powdery and very finely sealy with specific gravity=5.01(meas.) and 5.10(ealc.),and microhardness=16-35 kg/mm^3.Optically,it is nniaxial(-),Refrative index in sir Rs=26.6-29.5%,Rp=12.3-14.2%,colour index X=0.3114,Y=0.37848,λd=566mμ,Pe=14.4%.The chemical composition of muchuanite is given as follows;Mo 52.88,54.20;S 37.34 36.00;Fe n.d.,2.2;Si n.d.,0.5; H2O^+ 6.03,5.95;H2O^- 2.07,.00;total 98.59,99.85.Chemical and electron microprobe analyses gave the following formuls;MoS2,0.5H2O.Muchuanite is trigonal with space group C3^1=P3ml,unitcell parameters α=3.16A,c=43.60A,v=377.09A,z=7,and unit-cell containing 3.5 water molecules.The strongest lines given by X-ray diffraction pattern(d,A,intensity hkl)are 6.013(10,0.0.7);2.677(8.0.0.16);2.257(7,0.0.19);1.567(7,1.1.3);1.523(7,0.0.28);1.096(3,1.1.28);1.021(3,0.0.42).Muchuanite is syngenetic with feldspathic quartz sandstone.The mineral is named after the locality where it was discovered,i.e.Muchuan County in Sichuan Province.展开更多
Iron ehevkinite reported in this paper was discovered in a quartz syenite, which had intruded into Archaean marble, from a certain district in Hubei Province. It occurs as globular masses whose maximum weight can be a...Iron ehevkinite reported in this paper was discovered in a quartz syenite, which had intruded into Archaean marble, from a certain district in Hubei Province. It occurs as globular masses whose maximum weight can be as great as 1 kg. Iron ehevkinite has a black or pitch blaee color, with subconchoidal fracture. Specific gravity is 4.53±0.05. Microhardness 466.33-583.80kg/mm^2. Refractive index 2.02.It is metamiet, and the conversion temperature from metamiet state to erystallinity is 825℃. Chemical analyses give the following formula: (TR1/47Fe0.095^2+Th0.09Ca0.31U0.009Na0.11K0.01 Mn0.001)2.94(Ti1.44Fe0.57^3+Ta0.009Nb0.01)2.029(Si1.94Al0.06)2[O10.92(OH)1.05]12. It's chemical composition is characterized by a higher iron content (FeO+Fe2O3=17.58) in comparison with that in normal ehevkinite. Rare earth eontents, except for Ce, are also high, notably neodymium and lanthanum. The oxidation of Fe^2+ in iron chevkinite is caused by the water that had been subjected to irradiation and then found its way through fine cracks into the mineral The change in ionic radii involved in the oxidation of iron may be responsible for the metamietization of the mineral This interpretation accounts also for the eonstant association of a certain amount of water with metamiet minerals.展开更多
文摘Muchuanite, a new water-bearing molybdenum sulphide mineral, was discovered in aseries of molybdenum-bearing feldspathic quartz-sandstone of the Jurassic system,Sichuan Province, China. Muchuanite is darkly powdery and very finely sealy with specific gravity=5.01(meas.) and 5.10(ealc.),and microhardness=16-35 kg/mm^3.Optically,it is nniaxial(-),Refrative index in sir Rs=26.6-29.5%,Rp=12.3-14.2%,colour index X=0.3114,Y=0.37848,λd=566mμ,Pe=14.4%.The chemical composition of muchuanite is given as follows;Mo 52.88,54.20;S 37.34 36.00;Fe n.d.,2.2;Si n.d.,0.5; H2O^+ 6.03,5.95;H2O^- 2.07,.00;total 98.59,99.85.Chemical and electron microprobe analyses gave the following formuls;MoS2,0.5H2O.Muchuanite is trigonal with space group C3^1=P3ml,unitcell parameters α=3.16A,c=43.60A,v=377.09A,z=7,and unit-cell containing 3.5 water molecules.The strongest lines given by X-ray diffraction pattern(d,A,intensity hkl)are 6.013(10,0.0.7);2.677(8.0.0.16);2.257(7,0.0.19);1.567(7,1.1.3);1.523(7,0.0.28);1.096(3,1.1.28);1.021(3,0.0.42).Muchuanite is syngenetic with feldspathic quartz sandstone.The mineral is named after the locality where it was discovered,i.e.Muchuan County in Sichuan Province.
文摘Iron ehevkinite reported in this paper was discovered in a quartz syenite, which had intruded into Archaean marble, from a certain district in Hubei Province. It occurs as globular masses whose maximum weight can be as great as 1 kg. Iron ehevkinite has a black or pitch blaee color, with subconchoidal fracture. Specific gravity is 4.53±0.05. Microhardness 466.33-583.80kg/mm^2. Refractive index 2.02.It is metamiet, and the conversion temperature from metamiet state to erystallinity is 825℃. Chemical analyses give the following formula: (TR1/47Fe0.095^2+Th0.09Ca0.31U0.009Na0.11K0.01 Mn0.001)2.94(Ti1.44Fe0.57^3+Ta0.009Nb0.01)2.029(Si1.94Al0.06)2[O10.92(OH)1.05]12. It's chemical composition is characterized by a higher iron content (FeO+Fe2O3=17.58) in comparison with that in normal ehevkinite. Rare earth eontents, except for Ce, are also high, notably neodymium and lanthanum. The oxidation of Fe^2+ in iron chevkinite is caused by the water that had been subjected to irradiation and then found its way through fine cracks into the mineral The change in ionic radii involved in the oxidation of iron may be responsible for the metamietization of the mineral This interpretation accounts also for the eonstant association of a certain amount of water with metamiet minerals.
