5,300-year-old jade cong tubes and bi discs carved with exquisite detail using only stone tools and abrasive sand. Modern jewelers struggle to replicate the drilling and polishing techniques. This forgotten civilization proves China had complex societies before bronze.
Siyuwj, CC BY-SA 4.0, via Wikimedia Commons
A Neolithic Lapidary Problem
Between 3300 and 2300 BCE, a sophisticated culture flourished in the Yangtze River Delta. Known today as the Liangzhu, these people left behind no writing system, but they did leave thousands of finely worked jade objects that show a mastery of materials science. The primary material was nephrite, a mineral with a hardness of 6.0 to 6.5 on the Mohs scale. This presented a significant technological challenge, as the Liangzhu possessed no metal tools hard enough to carve it.
Their solution was abrasion. Scientific analysis shows the Liangzhu used harder minerals, likely quartz sand (Mohs hardness 7), and tools made of stone, wood, or bamboo to slowly grind the nephrite into shape. The process involved sawing, drilling, and polishing, all driven by manual labor. Microscopic examination of the artifacts reveals the techniques used, such as drilling holes from both sides of an object to meet in the middle. The final polish had a glossy, almost liquid luster that modern techniques, even with diamond abrasives, find difficult to replicate.
Ritual Forms in Stone
Two object types dominate Liangzhu burial sites: the bi and the cong. The bi is a flat, circular disc with a central hole. Their purpose is unknown, but they were often laid on the bodies of the dead in high-status tombs. The cong is a more complex shape: a square-sectioned tube with a circular hole bored through its length. These objects range from small, bracelet-like pieces to enormous examples. The largest, dubbed the "King of Cong," stands 8.9 cm high and weighs 6.5 kilograms.
The corners of the cong are decorated with face patterns, often interpreted as human-animal hybrids or deities. These designs are rendered in fine, shallow relief. Some carved lines are barely visible to the naked eye. The function of these objects is unknown, though a common hypothesis suggests the square cong represented the Earth while the circular bi represented the heavens. In one elite tomb at the Fanshan cemetery, archaeologists found 25 bi and 33 cong buried with a single individual.
The Archaeological Ruins of Liangzhu City, a UNESCO World Heritage site since 2019, reveals a complex society with urban planning, large-scale water management systems, and a clear social hierarchy expressed through these jade objects found in burials.
💡Fun Facts
The "King of Cong," the largest jade cong ever discovered, weighs 6.5 kilograms (14 lbs).
The Liangzhu culture had no writing, so the exact meaning of the symbols carved on the jades remains unknown.
Nephrite jade is harder than steel, which has a Mohs hardness of about 4 to 4.5.
The advanced Liangzhu culture likely collapsed around 4,300 years ago due to massive flooding of the Yangtze River.
The Liangzhu Museum is open from 9:00 AM to 5:00 PM, with last entry at 4:30 PM. It is closed on Mondays, except for national holidays. The Archaeological Ruins Park is open 9:00 AM to 5:00 PM, with last entry at 4:00 PM.
Admission
Admission to the Liangzhu Museum is free, but advance reservation is required. The Archaeological Ruins Park has an admission fee of 60 RMB.
Accessibility
The museum is a modern building and is generally accessible. The archaeological park is a large outdoor area, and visitors may want to use the available sightseeing buses.
