Looking into the Past with “Elemental Vision”

King Solomon’s secrets may be hidden in a shard of copper slag.

How, you may ask, would we know anything about a biblical King from a blacksmith’s slag—his metallurgical waste pile?

Going deeper than you or I might, down into the slag’s elemental composition, archaeologists have discovered evidence in the last decade that King Solomon may have had smiths skilled enough to build the Kingdom of Judah described in the Bible. A baptismal basin that stood on twelve bronze bulls. A hall of cedar. A magnificent ivory throne. Who knows what could have been possible?

A vision of history illuminated by a simple tool: the XRF gun.

Meet the XRF Gun: An Archaeologist’s Storytelling Device

X-ray fluorescence (XRF) is a non-destructive measurement technique in which one fires x-rays at a sample with an XRF analyzer, a tool commonly known as an XRF gun. The sample responds by emitting x-ray fluorescence, with each element giving off its own ‘fluorescent fingerprint.’ The XRF gun then reads the fingerprints and gives the user a detailed profile of the sample’s elemental composition. All of this happens in as few as 1-2 seconds—pretty good for laboratory-grade analysis.

Archaeologists use the ”elemental vision” of XRF to discover historical secrets. The test method is simple: fire x-rays, study the chemical makeup, and consider what your findings reveal given the historical context.

King Solomon’s secrets may not be so easy to discover, but expeditions to southern Jordan in the last decade by a joint team of archaeologists from Jordan and the University of California, San Diego (UCSD) have revealed that copper smelting in the neighboring kingdom of Edom, Judah’s bitter rival, progressed to an industrial level. 

Edomites lived in the highlands, according to sources dating back to the Book of Jeremiah. “Though you make your nests as high as eagles, I will bring you down from there,” the author wrote. But according to the ELRAP team’s findings, the people of Edom would swoop down into the dry river valleys below to mine precious copper. 

Khirbat en-Nahas, or “ruins of copper,” was the first site the archaeologist team excavated. What they unearthed was astonishing: a fortress formidable enough to rival those in Israel, Jordan, and Sinai, guarding 13 previously undiscovered copper mines, littered with more than 350 ancient mining tools. 

According to Dr. Thomas E. Levy and Dr. Mohammad Najjar, co-directors of several expeditions and founders of the Edom Lowlands Regional Archaeology Project (ELRAP), copper smelting in Edom achieved a level of artisanry and a scale of operations large enough to make a biblical version of King’s Solomon’s kingdom viable.

“We have discovered a degree of social complexity in the land of Edom that demonstrates the weak reed on the basis of which a number of scholars have scoffed at the idea of a state or complex chiefdom in Edom at this early period—and, by extension, a state in Judah,” Najjar and Levy wrote in their article “Edom and Copper” in Biblical Archaeology Review Magazine, 2006¹. 

How could Judah have survived centuries of war with Edom without achieving a mastery of copper smelting to rival their neighbors? Wouldn’t Judah have to be “a kingdom with ambition and the means of fighting off the Edomites,” as the archaeologists described it to The New York Times² in 2006? Or so the theory goes.

“Edom and Copper” sparked its own war upon publication, with archaeologists battling it out quite civilly in papers and lecture halls, at least in comparison to bronze age warfare, but with no less fierceness and passion.

“One ‘fortress’ does not make a Kingdom,” Eveline van der Steen, East Carolina University, and Piotr Bienkowski, University of Manchester, told The New York Times. 

Another vision of 10^th century Judah exists, one in which ancient Jews were more of a pastoral people. King Solomon? A chieftain, perhaps, rather than a king. Once, this view was blasphemous to biblical history. Then, thanks to contemporary archaeology, it became a compelling theory. Now, this “low chronology” view of Edom and Judah grapples with groundbreaking evidence expeditions have been gathering for the last 15 years, findings that indicate Levy and Najjar may be on to something.

Israel Finkelstein of Tel Aviv University, an advocate of the low-chronology movement, voiced his dissent as well, telling The New York Times that Levy & Najjar’s initial research did “not shed new light on the question of state formation in Edom.”

Was the King Solomon of the Bible a myth? Or, for once in contemporary archaeology, is the religious text more accurate than we know? To answer that question, we must journey to Faynan, Jordan, one of many historical sites across the world given new life by x-ray fluorescence.

Discovering King Solomon’s Mines—Or Rather, His Neighbors’ Copper Slag

Jordan is a part of what is known as the Levant. The term “levant” means rising in French, inherited from the Italian levante, which conjures up images of the rising sun in the East. In German, the term is translated as “morgenland,” or morning land. Levant is the name given to a cultural region that encompasses parts of modern Lebanon, Syria, Iraq, Palestine, and Jordan, defying geopolitical boundaries. Western religion dawned here. Depending on who you ask, Moses parted the Red Sea, Jesus thirsted for wine at a wedding, and Mohammed took one last look at Jerusalem before he ascended to the heavens, all on Levantine soil.

Archaeology in the Levant began as treasure hunting. Now it’s evolved into an endless quest for the historical treasures buried in the deserts and dry steppes where biblical kingdoms once flourished.

Here, archaeologists search for ceramics, which serve as veritable codices of historical data, as well as mud-brick homes and ruins of lost cities. And, as always, King Solomon’s mines, the legendary gold mines belonging to Solomon himself that writer H. Rider Haggard fantasized about. 

However, the team of San Diegan and Jordanian archaeologists set out in 2014 to learn about the past from a different source of historical evidence: copper slag.

Forgoing the search for lost cities themselves, the ELRAP team instead returned to the copper beds of Faynan in southern Jordan, where smiths, as they do, left their slag. Copper slag is mounds of metallic waste, a by-product of copper extraction by smelting. Impurities are cast away into what becomes small mountains of discarded metals. You may be thinking, “How can a monumental discovery have been found here, in a metallic mound? These aren’t exactly Solomon’s Mines,” and you’d be right. But buried in the elemental composition of these humble mountains are gems of historical insight that rival the riches Haggard dreamed up over a century ago. 

Brady Liss, an archaeologist from the UCSD Levantine and Cyber-Archaeology lab, was part of this expedition. He writes about the power of XRF’s “elemental vision,” as he calls it in his 2016 article: “Using X-Ray Fluorescence to Examine Ancient Extractive Metallurgy Practices: A Case Study from Iron Age Khirbat al-Jariya, Jordan.”³

A newer dig site, Khirbat al-Jariya, was his destination: once a copper ore district in Faynan around the 12 – 10^th centuries BCE, the site may have forged copper for the biblical kingdom of Edom, similar to Khirbat en-Nahas. Now, it’s home to 15,000 – 20,000 tons of slag. Khirbat al-Jariya is ideal for archaeometallurgy thanks to its “large copper smelting centers supported by networks of smaller, ephemeral mining camps.” Copper mines they may be, but to archaeologists, they are veritable gold mines of history, especially because Khirbat al-Jariya has been “primarily undisturbed since its Iron Age abandonment, leaving a relatively pristine record for archaeological research.”

Liss and his team used GIS, carbon dating, and lidar to study the smelting sites, but the key tool to their findings was XRF. Specifically, the Bruker TRACeR III-V+, a portable XRF gun.

“XRF has become a regular practice in investigating metallurgical remains and artifacts… both in the field and in the lab,” Liss writes.

How Archaeologists Harness the Power of XRF

How, then, do you make historical discoveries with XRF? Well, it’s quite simple really. Point and shoot. A piece of slag gives us an epic poem beginning in sparks, with the first copper smelted at the site, and ending in empires, or in this case small kingdoms like Judah.

Let’s take a look at how the ELRAP team made their discoveries.

First, they excavated a 1 x 1-meter rod of slag from one of the mounds, taking samples both from specific parts of the rod and from surrounding mounds. Digging down to the bedrock, the team retrieved enough slag to give them samples from every phase of copper smelting throughout the site’s history.

An XRF analyzer only fires at a single point and may miss key discoveries if the sample is not homogenous. For example, fire one at a rock and it will measure the stone effectively but may miss a vein of gold that runs through the other side. To capture stray copper shards in the “inherently heterogeneous” ancient slag, the team crushed each sample into a fine powder, grinding them with a mortar and pestle until they were representative of that piece of slag’s elemental makeup. Specifically, they were looking for how much copper each sample had, which would serve as an indicator of how successful copper smelting processes were at the time.

Once powdered, the copper slag sample was analyzed with the Bruker TRACeR III-V, which has “a rhodium anode to produce x-rays, and a SI-Pin detector for collecting fluorescence from the targeted sample.” The x-ray beam is 3 x 4 millimeters. Users can “control voltage (up to 40 kV) and current (between 0 – 60 µA) to enhance the detection of desired elements… the XRF system can be tailored to target specific elements of interest, maximizing their detection.”

Here are the test specifications the team used:

• Heavy elements: 40 kV, 13µA, with an acquisition time of 300 seconds
• Lighter elements: 15 kV, 35µA, with blue Titanium filter and a 300 second acquisition time

Once the testing was complete, they analyzed the results on a computer and found something remarkable: the smiths were getting better. Marked improvement in their copper smelting practices was evident.

A smith who has mastered the art of copper smelting will extract much more of the stuff in the process than a beginner. And their slag, their metallurgical waste, if you remember, will have much less precious copper. Looking at all the samples from throughout Khirbat al-Jariya, the archaeologists found a 70% decrease in copper waste in the slag over time. 

Now, it is important to note that the team’s findings do not definitively prove anything about Edom, Judah, or King Solomon, nor does Brady Liss make any such claims, beyond opening the doors to a palace of possibilities for metallurgically sophisticated Levantine societies in the 12^th – 10^th centuries BCE. 

What we do know, though, is that XRF made the difference in this interpretation of historical truths. Only two phases of copper production were found, but XRF analysis revealed that there was a dramatic difference in how successful they were, hinting at an evolution of coppersmithing practices.

A small story to tell. But it may be the beginning of recreating the world in which King Solomon and his Edomite rivals lived, one piece of copper smith’s slag at a time. And that is the power of XRF.

Illuminating the Past with the Technology of the Future

Let us revisit our biblical mystery for a moment. We set out to discover who King Solomon was—a king? A myth? A Bedouin sheikh? Or something else.

“Only a complex society such as a paramount chiefdom or primitive kingdom would have the organizational know-how to produce copper metal on such an industrial scale,” Drs. Levy and Najjar told The New York Times in 2006.

To Levy and Najjar, “the biblical references to the Edomites, especially their conflicts with David and subsequent Judahite kings, garner a new plausibility.”

Since they spoke out in 2006, their international team of archaeologists has continued to research and write passionately on the subject, publishing additional findings in 2010, 2012, 2014, 2016, 2020, and beyond, that all build the case for a reinterpretation of the minimalist, low-chronology vision for the Levant of biblical times. Recently, Erez Ben-Yosef, an ELRAP team member, discovered fresh evidence of Iron‑Age Edomite sophistication in the nearby Timna valley, a revelation in harmony with Levy and Najjar’s Faynan findings. “The scale of production tells us that there was something bigger than a few tribes here,” Ben-Yousef told The New Yorker.⁴

But not everyone is convinced.

“Is this early Edom?… Why not Midian; Amalek, Kedar, Paran, Teman?” low-chronology scholar Finkelstein wrote in a reply to Ben-Yosef’s work in 2020,⁵ once again casting shadows on the team’s discoveries.

We have no answers. All we have are the strikes of the smiths’ hammers. Each time, more accurate. Each age, more copper preserved. And in the days of King Solomon, perhaps just enough to armor the kingdoms of biblical legend.

“Archaeology is paradoxically rooted in the past but dependent on the future,” Brady Liss writes, the future being technologies like XRF that make these discoveries possible.

We live in an age where people want to reconnect with their origins—we trace our family trees on Ancestry.com, map out our lineages with 23 and Me, and cultivate long-lost cultural identities.

X-ray fluorescence and the technologies of the future can, as Liss so presciently wrote, connect us to that past, to our ancestors and our people.

To our stories—and everyone, from smiths toiling in desert mining camps under the night sky, to Kings asleep in their beds, is connected.

We just have to look closer, ask the right questions, and the artifacts will answer—the truth written in their very elements. 

To explore the Faynan dig site, its history, and the team’s findings in a stunning interactive digital experience, visit the UCSD team’s website.