Scientists Rediscover a Lost Ming Dynasty Technique for Folding Gold Into Satin

Researchers in China say they have cracked the secret behind a lost Ming Dynasty goldsmithing technique that could fold sheets of gold into intricate, satin-textured shapes — a method so refined it has puzzled scholars trying to reproduce it from surviving artifacts.

The technique, known as jin zhe si, produced ultra-thin gold foil that was repeatedly folded and corrugated to create a soft, satin-like surface, rather than being engraved or embossed in the conventional way. A team from the Gemmological Institute at the China University of Geosciences in Wuhan reconstructed the process by studying a pair of gourd-shaped gold earrings recovered from the tomb of Prince Zhu Zairong, a Ming nobleman who died in 1545, in Hubei Province.

Combining microscopic analysis of the original ornaments with experimental archaeology and reverse engineering, the researchers — Tian Zhihao, Ren Kai and Jiang Zhenyu — tested foils of gold, silver and aluminum under identical conditions to see which metal could withstand the punishing sequence of folds. Only gold of very high purity, they found, could be folded again and again into the complex three-dimensional forms the style demanded without cracking or tearing.

"Only high-purity gold could be folded repeatedly into the complex three-dimensional shapes required without cracking or breaking," the team concluded, explaining that the ornaments' distinctive satin texture was the deliberate result of folding and corrugating the metal, not of tooling its surface. The finding helps explain why the technique was reserved for elite objects: it required not only exceptional craftsmanship but also access to gold refined to a purity few workshops could achieve.

The study, published in the journal npj Heritage Science, bridges a gap between historical descriptions of Ming metalworking and the physical evidence buried in aristocratic tombs. Chinese goldsmiths of the era were renowned for filigree, granulation and other virtuoso methods, but jin zhe si had faded into obscurity, its precise mechanics unclear to modern conservators.

Beyond solving a historical puzzle, the researchers say their work has practical value for preserving and, potentially, reviving traditional Chinese goldsmithing. By documenting exactly how the folds were made and why high-purity gold was essential, the study gives contemporary artisans and conservators a roadmap for understanding — and reproducing — a craft that had been effectively silent for centuries. It also underscores how much technical sophistication is embedded in objects often admired only for their beauty, revealing the Ming workshops as centers of materials know-how as much as artistry.