X-Ray “Gun” Identifies A Shipwreck’s 800-Year-Old Knockoff Ceramics
Chemical analysis of qingbai wares aboard a Java Sea shipwreck identifies, with shocking precision, the origin of these ancient treasures.
Ceramics recovered from a ship that sank in the Java Sea some 800 years ago are now being traced back to their point of origin, revealing the trade routes that governed Asian markets during the 12th century. Image Credit: Pacific Sea Resources
In the late 1980s, a team of anglers trawling for fish off the coast of Indonesia stumbled upon a most unexpected catch: an ancient ship that likely met its end in the Java Sea some 800 years ago.
The vessel’s untimely demise came mid-journey, leaving no definitive record of its origin or destination. But by mining the treasure trove contained within its ancient hull, researchers are slowly unraveling the ship’s story from start to finish.
In a study published today in the Journal of Archaeological Science, a team of scientists pinpoints the origins of several of the Chinese ceramics on board. The chemical composition of the ship’s glazed, bluish-white qingbai wares shows they were forged at four different kiln sites across China—and while some were high-quality, luxury items destined for the social elite, others appear to be more akin to counterfeits, likely mass produced to meet rising demand in markets abroad.
“I think these are brilliant results,” says Elisabeth Holmqvist, an archaeologist and material scientist at the University of Helsinki in Finland who was not involved in the study. “This is when geochemical data really becomes valuable for archaeological questions: It provides the evidence, and then we can go back to the socioeconomic context. That’s the greatest value in this kind of research.”
Qingbai ceramics from the Field Museum's Java Sea shipwreck collection. X-ray fluorescence can help pinpoint the source of these wares by analyzing their chemical composition. Image Credit: Kate Golembiewski, Field Museum
Before it sank to its watery grave during the 12th century, the ship that bore these goods was probably en route from southeastern China to the Indonesian island of Java, ferrying a hefty hoard of iron, resins, ivory, and tin ingots. But none of these prizes could match the most substantial cache of all: a collection of 100,000 ceramic vessels, including an assemblage of qingbai porcelain.
Not all qingbai are created equal, however. While authentic qingbai porcelain had its heyday in Jingdezhen in China’s Jiangxi province starting around the mid-10th century, as the style increased in popularity, trendspotting kilns across south China began churning out their own imitation ceramics in the hopes of breaking into overseas markets. It wasn’t uncommon for trade ships like this one to carry porcelains from multiple provinces in the same hull.
Though some of these forgeries were set apart by a notable dip in craftsmanship, a good number of others were apparently convincing counterfeits, making it nearly impossible to determine where these porcelains were fired by eye alone—especially when they’ve spent the past few hundred years at the bottom of the sea.
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To accurately source the ceramics, a team led by anthropologists Wenpeng Xu and Lisa Niziolek analyzed the chemical composition of 60 porcelain fragments from the shipwreck and mapped each back to its birthplace. In a way, while you can take a ceramic out of a kiln site, you can’t take a kiln site out of a ceramic: Each specific location likely used unique recipes for its clays and glazes, mixed with materials specific to that region.
Rather than employing a more destructive technique that might require grinding up the artifacts, the team used a portable x-ray fluorescence spectrometer—which looks like something like a raygun out of a 1980s sci-fi film—that beamed x-rays at the ceramics to assess the unique chemical signatures within. They then compared these chemical fingerprints to those from 69 qingbai gathered from known kiln sites around China. If a fragment from the ship chemically resembled one from a kiln site, the team considered it a match.
Portable x-ray fluorescence spectrometers look a little bit like laser guns. By shooting x-rays into a material, they can non-invasively determine its chemical composition. Image Credit: Kate Golembiewski, Field Museum
In the end, the researchers determined that three types of qingbai porcelains had boarded the doomed ship, by way of four distinct pottery-producing locations: Jingdezhen, Dehua, Huajiashan, and Minqing. Niziolek was surprised to see that the technique was even sensitive enough to differentiate between porcelains that came from the same city, but had been fired in kilns just five miles apart.
As expected, the highest-caliber porcelains tended to hail from Jingdezhen—home of the OG qingbai—while the other kiln complexes more reliably produced replicas in bulk. Xu thinks it’s no accident that such a wide range of ceramics ended up on the same ship: “Merchants were aware of what products would do well in which markets [overseas],” he says. The most prized wares would have sold to the highest bidder, while lower-quality wares were meant for the masses.
For Niziolek, these subtle, yet conscious, discrepancies are proof of remarkable economic and cultural flexibility. Chinese potters weren’t just robotically manufacturing porcelains: They were engaging in a global market, and responding to the ever-changing needs of their consumers.
“This gives us a new perspective on how globalization evolved,” Xu says. “The world before the modern era… was much more interactive than we once thought.”
To build a reference map for the ceramics found in the Java Sea shipwreck, the researchers first tested their technique on qingbai gathered from known kiln sites around China. Image Credit: Kai Li
Linking porcelains back to their roots may seem niche, but this research could set precedent for other applications—including modern forensics, says Anikó Bezur, a conservation scientist at Yale University who was not involved in the study. For instance, portable x-ray fluorescence spectrometers could come in handy for identifying illegally trafficked archaeological goods, and uncovering their true country of origin.
“These simple measurements allow objects to start telling their own stories—of when these materials were made, and where they were coming from,” says Francesca Casadio, a chemist and conservation scientist at Chicago’s Center for Scientific Studies in the Arts who was not involved in the study. “It’s information that can sometimes rewrite history.”
