"Iran produces oil and has natural bitumen. Asphalt is an organic gelatinous substance, which can be liquid, semi-solid, or solid, with good high temperature stability, low temperature crack resistance, durability, adhesion, elasticity and other characteristics. The Iranians discovered this secret early on, and they even made artifacts out of asphalt. ”
"With natural asphalt that is neither soft nor hard, it is most suitable to hammer gold and silver materials as utensils. Until now, Iranian craftsmen still use this technique to make silver, bronze and so on. ”
"There was no asphalt in China at that time, and the earliest gold and silverware production was made using its own mature casting technology. After the Persian artifacts and technology spread to China, China began to learn imitation, the bottom mold is made of rosin and some other materials, but also not soft and hard bottom mold, with the characteristics of asphalt. ”
Excerpt from: Qi Dongfang. "I'm at the Archaeological Site: Ten Lectures on the Archaeology of the Silk Roads." Apple Books.
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