A recently discovered copper awl from a Middle Chalcolithic burial at Tel Tsaf, Jordan Valley, Israel, suggests that cast metal technology was introduced to the region as early as the late 6th millennium CalBC. This paper examines the chemical composition of this item and reviews its context. The results indicate that it was exported from a distant source, probably in the Caucasus. (...)
The earliest extractive metallurgy in the southern Levant is typically connected with the Late Chalcolithic period (ca. 4500–3800 CalBC) and reliable 14C dates show that the prestige items were manufactured as early as 4350–4250 CalBC [28]–[29]. In the southern Levant, an extremely elaborate tradition developed using lost-wax casting of combining copper ores with high antimony or nickel content with arsenic rich ores to cast prestige objects, as known at various sites in southern Israel [30]–[33]. (...) The elaboration of south Levantine Late Chalcolithic metallurgy means that with our current archaeological record, the peak of the technical evolution of copper metallurgy is set at its beginning. In our opinion, this suggests that large parts of the technological evolution of metallurgy have not yet been discovered. Indeed, the Tel Tsaf awl dated to ca. 5100–4600, centuries earlier, would thus fill an important gap in the picture. However, the high percentage of tin in the awl could be used to argue that the item was an intrusive object from a much later period—although during the excavation no disturbances were documented and the context was sealed by mudbricks and stone slabs and cobbles.
Recently, new data on very early copper artifacts in the northeastern Near East and the Balkans indicate that tin was found in some of the early metal items known in this area [35]–[37]. Another example comes from the Late Neolithic mound of Aruchlo I in Georgia, 5800–5300 CalBC [38]. This is a heavily corroded, small, ring-shaped bead, and therefore it is unclear whether it was cast or hammered. XRF-analysis identifies copper, iron, arsenic and a larger amount of tin. It was suggested that the object was made from a polymetallic raw-material, i.e. a natural copper-tin alloy [38]–[39]. A final analysis of the bead recently confirmed a copper-based (84.991%) alloy with high amounts of tin (8.350%) as well as arsenic (3.016%) and iron (3.643%) [40].
Even though it could be argued that the items from Aruchlo I and Tel Tsaf are later intrusions which were brought into earlier archaeological layers by post-depositional processes, this seems to be less plausible because there are no known later settlement traces at either site. Since artificial alloying would also be very improbable at such an early time, a natural copper-tin alloy is, at the moment, an interpretation worth considering. Copper sources with a natural tin-copper alloy are known inter alia in Mušiston, Tajikistan [41]–[42]. The easy availability of tin and the knowledge of natural tin-copper alloys could be one reason why the alloying of tin-bronze took place in the Caucasus significantly earlier than in neighboring regions, namely in the 4th millennium CalBC [43].
If one accepts the Aruchlo I bead as non-intrusive, it demonstrates the possibility of the extraction and use of natural tin-copper alloys as early as the 6th millennium CalBC. This, in turn, also opens the possibility that the item from Tel Tsaf was made from a natural tin-copper source and transported to the Jordan Valley via long-distance exchange networks, which also brought obsidian, groundstone items and other goods from Armenia, Anatolia and Syria through the Levantine Corridor.