Freibergit a jamesonit z historického ložiska stříbra Šebestěnice u Čáslavi (Česká republika)
Jiří Sejkora, Jiří Litochleb, Milan Fišera
Freibergite and jamesonite from the historical silver deposit Šebestěnice near Čáslav, Czech Republic Small Ag-bearing base metals ore deposit Šebestěnice (SSW near Čáslav, central Bohemia, Czech Republic) was last mined in 16th - 18th century and its mineralogy is not known in detail. The ore mineralization close to the Kutná Hora type is represented by quartz of two generations (± dolomitic carbonate) with disseminated aggregates of ore minerals: pyrite, sphalerite, galena, chalcopyrite (aggregates 0.X - 3 mm) and rare freibergite and jamesonite (up to 1 mm in size). The variable Ag contents are chararacteristic of Fe-dominant freibergite, its chemical composition on the basis 29 apfu can be expressed as (Ag5.94Cu0.06)Σ6.00[Cu4.22(Fe1.81Zn0.22Cd0.02)Σ2.05]Σ6.27 (Sb4.17As0.07Bi0.01)Σ4.25(S12.45Cl0.03)Σ12.48 (Ag-rich) and (Ag3.46Cu2.54)Σ6.00 [Cu3.86(Fe1.66Zn0.37Cd0.01)Σ2.04]Σ5.90(Sb4.14Bi0.02)Σ4.16 (S2.93Cl0.02)Σ2.95. (Ag-poor). Acicular jamesonite crystals are homogenous and its empirical formula on the basis 25 apfu (Pb3.78Ag0.01)Σ3.79Fe0.95(Sb6.09As0.01)Σ6.10S14.15 is close to ideal composition of this mineral species.