MERCURY AND SMALL-SCALE GOLD MINING AT ANCIENT SARDIS, TURKEY

Cinnabar was mined and retorted to produce mercury in ancient Turkey more than 8000 years ago. Both the Greeks and Romans mined cinnabar at Sizma (~6300 aC) and near Konya, an ancient 3 m²mercury retort, cut into marble, was found. Geologically, there are seven mercury districts in Turkey; however, production ended in the 1970s.

Modern uses for cinnabar and mercury are numerous; however, in the Byzantine world, cinnabar was used as a pigment (vermillion) and to produce mercury that was used for gilding or amalgamation of fine-grained alluvial gold. At Sardis, alluvial gold mining dates to ~700 aC and continues today, and, as recently as 1984, sluice concentrates at Sardis were amalgamated. Geology and availability of mercury, a mercury retort, regional Roman use of mercury for amalgamation, and the very fine-grained (~0.03 mm) alluvial gold at Sardis all indicate that amalgamation must be reconsidered as the ages-old mining technology that supplied alluvial gold to ancient Sardis’ refineries.

Inductively Coupled Plasma (ICP) geochemical studies in Colombia and Perú indicate that gold from alluvial sources may contain ~5000 ppm Hg sourced from cinnabar/mercury outcrops, underground coal fires, alluvial gold mining, or volcanic eruptions. However, modern amalgam (Hg+Au) in the gold pan contains >300,000 ppm Hg—this amalgam must be burned (refogado), as would have been done in the past, to volatilize the mercury, leaving end-product gold with only trace amounts of mercury. Prehispanic gold artifacts from museums in Bogotá and Lima typically contain <20 ppm Hg—consistent with a reduction in the mercury content during amalgam burning. Therefore, we are similarly using ICP to determine the metal content, particularly Pt and Hg, of end-product Byzantine gold to interpret the mining technology used at ancient Sardis.