Before quantum computing and self-driving cars, a different kind of cutting edge was sweeping the world: metal smithing. To ancient people living over 6,000 years ago, mining raw metal from the Earth and carefully melting it to craft into currency, tools, and even ornate ritualistic objects, was the height of innovation.
In a recent study in the Journal of Archaeological Science: Reports, scientists describe an archaeological site that may have been the first place in the world to host this technology's secret sauce — a furnace.
Chemical analysis of remnants at an ancient copper-smelting site in Israel points to a two-stage crafting process for metal objects. Not only that, but the site appears to have used copper ore from mines located over 60 miles away.
The combined evidence of an elaborate supply network and the specialized, multi-step process is a testament to the importance of this ancient, cutting-edge technology, the researchers say.
Melting metal is no easy feat. Lead researcher on the study and professor of archeology at Tel Aviv University Erez Ben-Yosef said in a statement the reality is an incredibly delicate and precise process that requires serious skill.
"It's important to understand that the refining of copper was the high-tech of that period. There was no technology more sophisticated than that in the whole of the ancient world," Ben-Yosef says. "Tossing lumps of ore into a fire will get you nowhere. You need certain knowledge for building special furnaces that can reach very high temperatures while maintaining low levels of oxygen."
Older studies suggest people living some 6,000 years ago in what is now the Middle East used clay crucibles — which resemble vases — for smelting copper ore. But when archaeologists excavated this site in 2017, they found evidence of a different kind of technology: a small furnace made of tin and clay.
"This provides very early evidence for the use of furnaces in metallurgy and it raises the possibility that the furnace was invented in this region," said Ben-Yosef.
Reconstructing history — The archeologists first conducted a chemical analysis on uncovered remnants of the site's metal works using a portable X-ray instrument. After studying 14 crucible and 18 furnace fragments, as well as metallurgy's glass-like byproduct, 'slag,' the team retraced these ancient innovator's steps to imagine what their process would've looked like.
In the study, they describe there was likely a two-step metal-smithing process that began with melting ore in a clay-lined, pit furnace, and then scraping it into a smaller crucible to be remelted. Finally it would be poured into a sand-based mold in the ground to cool and form transportable lumps.
The irregularity of these final forms and the lack of other casting remnants led researchers to believe that this site was not constructing objects themselves, but instead processing the metal for other communities to use.
In addition to the copper found, the team also found reoccurring signatures of phosphorous, which they think may have come from burnt bones. While there isn't enough evidence to know for sure, the researchers write that it's possible an animal sacrifice was made during the smelting process as a form of organic fuel.
The analyses also reveal the site used an ore found more than 60 miles away, in what is now the Jordan Valley. In future centuries, these smelting sites and mines would move closer together for practical and economic reasons, but the researchers write that the more ancient, long-distance network uncovered here is further evidence that the process of smelting these metals was highly specialized and safe-guarded by each community — like a secret family recipe, or how a tech company protects its intellectual property with NDAs.
"At the beginning of the metallurgical revolution, the secret of metalworking was kept by guilds of experts. All over the world, we see metalworkers' quarters within Chalcolithic settlements, like the neighborhood we found in Beer Sheva," explains Ben-Yosef.
A first... or not? — The evidence suggests this Israeli site may be one of the first in the ancient world to begin using a furnace for copper smelting. But the technology may have been invented and used around the same time in neighboring regions, Ben-Yosef says. Nevertheless, the discovery cements a place in history for this community as an ancient, "technological powerhouse," he adds.
"[T]here is no doubt that ancient Beer Sheva played an important role in advancing the global metal revolution," he says.
Abstract: Recent discoveries at Horvat Beter (Beersheva, Israel) shed new light on the earliest phase of Southern Levantine metallurgy (second half of the 5th millennium BCE). Multiple fragments of furnaces, crucibles and slag were excavated, and found to represent an extensive copper smelting workshop located within a distinct quarter of a settlement. Typological and chemical analyses revealed a two-stage technology (furnace-based primary smelting followed by melting/refining in crucibles), and lead isotope analysis indicated that the ore originated exclusively from Wadi Faynan (MBS Formation), more than 100 km away. These observations strengthen previous suggestions that metallurgy in this region started with furnace-based technology (possibly not locally invented). Furthermore, the absence of any artifact related to the contemporary industry of copper-based alloys indicates a high degree of craft specialization, and together with other regional observations testifies to the important role of metallurgy in the society of the Beer-sheba Valley during this formative time.