Crystallochemicaly investigations of the sphalerites from the polymetallic Pb-Zn ore deposit Kiževak

With the X-ray, chemical and spectrochemical method there were investigated monomineral concentrations of the brown and yellow sphalerite varietys from the polymetallic Pb-Zn ore deposit Kiževak from the different horizons at 670, 690 and 710m. There were calculated sphalerite unit cell dimensions for which it was confirmed that increase with the increasing of the Fe, FeS and (Fe,Mn,Cd)S contents and that decrease with the increasing of the Cu content. Sphalerite compositions and their unit cell dimensions are more or less different at different depths, and also they are different for the brown and yellow varietys. These differences are also manifested at mutually different slopes of the lines which are representing the dependence of the unit cell dimensions by sphalerite compositions from the different horizons, and also for sphalerites of the different color. These mutually different slopes indicate to the different chemical compositions (from which is of the most significance the Fe content), but also probably to the different formation conditions of the sphalerite, and according to that to the different formation conditions of the individual horizons and varietys of this ore deposit. Contents of the (Fe,Mn,Cd)S most probably are not useful for the objective conclusions at the crystallographical sense, because they show considerable lower “ending” unit cell dimensions than Fe and FeS contents, which are showing the same. Calculated unit cell dimensions from the X-ray investigations are considerable bigger related to that which are calculated from the equations from the literature datas, while that difference decrease with the increasing of the Fe and FeS contents

Crystallographicaly-chemical characteristics of sphalerites from the polymetallic Pb-Zn ore deposit Kiževak (Raška, Serbia)

With the X-ray, chemical and spectrochemical methods there were investigated monomineral concentrations of sphalerites from the polymetallic Pb-Zn ore deposit Kizevak (Raska, Serbia). These sphalerites are from the different horizons of 670, 690 and 710m. Their colour vary from yellow, brownish-yellow, brown to brownish-red. Obtained crystallographic parameters are within following ranges: a0 = 5.4184(6) – 5.4195(6)Å and V0 = 159.08(5) – 159.18(6)Å3. Obtained chemical contents are within following ranges: FeS = 1.29 – 12.28 mol.%; MnS = 0.08 – 0.21 mol.%; CdS = 0.23 – 0.32 mol.%; CuS = 0.01 – 0.30 mol.%; In = 0.0006 – 0.0600 % and Ga = 0.0004 – 0.0090 %. It was confirmed that crystallographic parameters increase with the FeS content and decrease with the CuS content

Crystal structure and chemical composition of ludwigite from Vranovac ore deposit (Boranja Mountain, Serbia)

The crystal structure of ludwigite from Vranovac ore deposit (Boranja Mt., Serbia) was refined using the X-ray powder diffraction (XRPD) Rietveld method in the space group Pbam to a final RB=7.45% and RF=5.26%. It has the unit cell dimensions of: a=9.2515(2) Å; b=12.3109(2) Å; c=3.03712(7) Å; and V=345.91(1) Å3. The calculated distances and angles are mostly in good agreement with the Mg2+-Fe2+ substitutions across the M(1) and M(3) sites, as well as with the Fe3+-Al3+ replacement in the M(4) site. However, the mean observed M(2)-O distance is considerably shorter than prescribed, due to a slight increase of the Fe3+ content in the M(2) site. Such replacement was compensated by slight increase of the Fe2+ content in the M(4) site, resulting in the (Mg1.48Fe2+0.46Fe3+0.05Mn0.02)2.01(Fe3+0.94Fe2+0.04Al0.02)1.00B1.00O5 composition. The formation temperature was estimated to be about 500–600°C. The influences of the various chemical compositions to the crystallographic parameters, M-O distances, M(3) and M(4) sites shift, distortion parameters and estimated valences, were also studied and compared with other reference samples