Cord saw technique with abrasive slurry confirmed by experimental archaeology. Interior surfaces contain gently curved, shallow concave markings—cord saw marks from the manufacturing process Craftsmen used flexible cord or string (likely plant fiber or sinew) drawn back and forth across the stone in a continuous sewing motion The cord delivered an abrasive slurry of water mixed with quartz sand, garnet, and corundum—all harder than nephrite on the Mohs scale
How did Neolithic craftsmen hollow out these tough nephrite tubes? They used cord saws with abrasive slurry: flexible cord (likely plant fiber or sinew) drawn back and forth while quartz sand, garnet, and corundum particles wore through the stone. Unlike rigid saws, flexible cords bow under tension, leaving curved grooves inside the tubes that researchers call "fingerprints of the craftsman." The two base holes were drilled with hollow bamboo or stone bits. Modern experimental archaeology has fully confirmed this process produces marks indistinguishable from genuine artifacts. Flawless 1mm walls required months of careful continuous labor on a single piece.
Key Facts
- Interior surfaces contain gently curved, shallow concave markings—cord saw marks from the manufacturing process
- Craftsmen used flexible cord or string (likely plant fiber or sinew) drawn back and forth across the stone in a continuous sewing motion
- The cord delivered an abrasive slurry of water mixed with quartz sand, garnet, and corundum—all harder than nephrite on the Mohs scale
- The moving cord carried abrasive particles against the stone surface, wearing through material via friction
- Production process: rough shape the stone, drill a small hole through it, thread cord through and saw off the center core based on a guideline
- Unlike rigid saw blades that cut straight lines, flexible cords bow under tension, leaving curved grooves
- Those curved marks preserved inside jade objects for 5,000 years are described as 'fingerprints of the craftsman'
- Modern experimental archaeology has confirmed the process entirely—researchers produced tool marks on nephrite indistinguishable from genuine Neolithic artifacts
- The two small paired holes at the base were drilled using hollow bamboo or stone drill bits rotating against abrasive slurry
- Ancient Chinese tradition described jade working in four sequential verbs: cutting, grinding, carving, and polishing
- Flawlessly smooth, semi-translucent millimeter-thin walls required months of careful continuous labor on a single object
Source: What Were These 5,000-Year-Old Jade Tubes Really For? by Curious Being