Thracian golden wreath from Kabyle, Bulgaria: chemical composition

The chemical composition of a Thracian gold wreath from Kabyle dated to 4th century BC (Thracian age in Bulgaria) was analyzed. Au, Ag and Cu concentrations were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES) while As, Bi, Cd, Co, Fe, Zn, Sn, Sb, Ga, In, Mn, Mo, Ni, Pb, PGEs (Pt, Pd, Ir, Re, Rh, Ru), Se, Te, Ti, U, W, Zn, and Zr concentrations – by inductively coupled plasma-mass spectrometry (ICP-MS). Data showed that the wreath was made of very well purified gold alloy (Au content between 97.1 and 99.9%). The bivariate plot of the Pd and Pt concentrations showed that the gold used for these artefacts came from four different sources. Due to the lack of analytical data about the platinum group elemental (PGEs) concentrations from different gold sources in Bulgaria it was impossible at this stage to identify the geographical location of the four sources for the gold wreath.