Scientists have uncovered the secret behind the Ming dynasty’s gold jewellery

The secret lay in a special technique known as Jin zhe si: the craftsmen folded and crimped very thin sheets of gold to create an openwork pattern and a distinctive ‘fabric-like’ texture.

The study was published in the journal npj Heritage Science.

Filigree is usually made from fine metal threads or wire: these are twisted, bent and soldered together to create a lace-like pattern. However, the researchers found no wire in the Ming-era jewellery. The surface was made of the finest gold foil, folded into small, regular pleats.

To test their hypothesis, the team studied ancient earrings from the tomb of Prince Zhu Zai-zhong, who died in 1545, and then attempted to recreate the entire process. As a result, the scientists succeeded in making a replica of a gourd-shaped earring, which matched the original in shape, texture and weight, differing by only about one gram.

Details

Researchers from the China University of Geosciences studied a pair of gold earrings from the tomb of Prince Zhu Zaizhong. Each earring consisted of a pendant in the shape of a double gourd: a hollow gold body, topped with leaves and vines, with the entire structure attached to a gold hook.

Such jewellery was not merely decorative. It demonstrated the skill of Ming-dynasty jewellers and the status of their owners. Hubei Province was an important centre for the burials of princes and the nobility of that era, and finds from such tombs provide a wealth of information about the court and aristocratic culture of 16th-century China.

Researchers examined the earrings under a stereomicroscope and produced new technical drawings. Under magnification, it became apparent that the surface of the jewellery was covered with fine, regular ripples. These ripples were not formed by soldered wire, as in classical filigree, but by folds in the gold itself. There was also no filler inside the jewellery.

In other words, the craftsman did not use gold wire to form a pattern. Instead, he worked with a thin sheet of gold: he folded it, created a corrugated surface, and then shaped the piece as required. Therefore, Jin zhe si resembles filigree visually, but technically it is a different method of metalworking.

After analysing the original, the researchers applied reverse engineering. This means that they did not simply describe the finished piece of jewellery, but attempted to reconstruct, step by step, how the craftsmen of the Ming dynasty might have made it: what materials they used, how they folded the gold, how they shaped the body of the earring, and how they achieved the desired texture.

A key factor turned out to be the properties of the material itself. The scientists attempted to replicate the process not only with gold, but also with silver and aluminium foil. The silver and aluminium either tore or failed to hold their shape. High-purity gold, however, could be folded repeatedly without cracking, and it retained its complex corrugated structure.

Put simply, the secret lay not only in the craftsman’s hands, but also in the material itself. Gold is sufficiently malleable: it can be severely deformed, made very thin, folded and bent without breaking. It was precisely this that enabled the Ming jewellers to create the effect of delicate ‘metallic lace’ without using actual wire.

According to the authors’ estimates, once a craftsman had mastered the technique, it could take around one day to make a single earring of this kind. It was not a simple task, but the technique was sufficiently refined to enable the creation of intricate jewellery for elite clients.

Why this is important

The research shows that antique jewellery can be studied not only as works of art, but also as technological artefacts. By examining microscopic folds, cracks and traces of processing, scientists can reconstruct the craftsman’s actions, even if the technique itself has long since fallen out of use.

This is important for the history of the craft. The Jin zhe si technique was mentioned in historical sources, but it remained unclear exactly how it worked. Now, researchers have demonstrated a possible production process and verified it experimentally, rather than relying solely on textual evidence.

The research also helps to describe museum objects more accurately. Just because a piece of jewellery looks like filigree does not necessarily mean it is made from wire. In the case of Jin zhe si, a similar effect was created differently — by folding and crimping gold foil. This changes our understanding of just how diverse Ming jewellery techniques were.

Background

The Ming Dynasty ruled China from the 14th to the 17th century. This was a period of highly developed court and aristocratic art, including intricate artefacts made from gold, jade, porcelain and other precious materials. Jewellery from the lavish tombs demonstrates that the craftsmen of that era were masters of very delicate metalworking techniques.

Classical filigree is known in many cultures. It is made from fine wire, which is twisted, bent and soldered to a base. Consequently, filigree jewellery appears light, lacy and highly intricate.

However, the find from Zhu Zai-zhong’s tomb revealed a different approach. The pattern looked like filigree but was created without wire. This makes ‘Jin zhe si’ a distinct technique, rather than simply a variation of conventional filigree.

The study also explains why high-purity gold was specifically required for this type of work. Other metals tested in the experiment could not withstand such repeated folding. This means that the choice of gold was not merely a matter of luxury, but also a technical necessity.

Source

Study: Zhihao Tian et al., “Restoration of Ming dynasty Jin zhe si: a lost Chinese goldsmithing technique”, npj Heritage Science, 2026.