Tiny Brass Droplets in Three Guangzhou Crucibles Give East Asia’s Earliest Evidence of Brass Production

Archaeologists excavating an ancient metal workshop in Guangzhou, China, found about 80 crucibles. Tiny brass droplets trapped on the surfaces of three of them date to the ninth and tenth centuries. Brass is an alloy of copper and zinc. Written Chinese sources mention brass as early as the tenth century, but the previous oldest archaeological evidence dated only to the sixteenth century, according to Archaeology Magazine.

A workshop at the Nanyue Royal Palace site

The team, led by Hongyan Xiao of Peking University, published its results in the journal Antiquity (volume 100, issue 413, October 2026). The workshop sits at the Royal Palace of the Nanyue Kingdom in Guangzhou. A semi-subterranean furnace from the same workshop dates to the seventh through tenth centuries. The crucibles are small, holding only 0.2 to 0.3 liters, and workers made them from china-stone clay mixed with rice husk and straw and coated them with lime-rich layers.

How researchers identified the brass

Portable X-ray fluorescence showed that zinc in the crucible interior residues rose sharply around the turn of the ninth century and reached about 32 percent, while tin and lead declined. Earlier crucibles typically held less than 0.1 percent zinc. Scanning electron microscopy then found brass droplets in the slag. One group of crucibles holds near-pure copper and brass with 11 to 17 percent zinc. Another group holds a copper, zinc and tin alloy with 2 to 4 percent tin and 11 to 15 percent zinc.

The authors argue that workers made the brass by cementation. They placed copper or bronze in a crucible with zinc ore and charcoal, and heating above about 950 degrees Celsius turned the ore into zinc vapor, which combined with the copper. Lead isotope ratios match the Cathaysia province, which suggests a local or regional source for the metal.

Why it matters

The authors suggest that an institutionalized industry and maritime trade routes helped bring brass-making to southern China. Xiao said that understanding how people first learned to produce brass reveals how knowledge spread, and that a single crucible contributes to broader questions about the history of technology and human innovation.

The limits of the evidence

The paper presents three well-preserved brass-making crucibles in detail, out of 51 that the team tested. The authors note that portable X-ray fluorescence alone cannot show that the zinc relates to brass-making, so the case rests on the microscopy and microstructure findings. They infer the zinc ore, most likely lead-free calamine, and no lids have turned up, so their use remains unverified. Lead isotopes reflect mixed copper and zinc sources and cannot pinpoint the ore origin. The claims about an official industry and about maritime influence are interpretations that rest partly on historical texts.

Source: Archaeology Magazine, 18 August 2026, reporting on Xiao et al., “Brass technology transmission via maritime routes: crucible evidence from southern China,” Antiquity 100(413), 2026, pp. 1385-1403 (DOI 10.15184/aqy.2026.10373).