Xianyang's bronze warrior head is unique national treasure

According to X-ray fluorescence testing, the statue contains 84.6 percent copper, 12.3 percent tin, and 2.1 percent lead, which matches Qin bronze casting techniques.

Yang said its intricate details suggest highly precise lost-wax casting: a wax mold carved with patterns was coated in clay and heated to melt the wax. It was then filled with molten copper, and the clay was removed.

Traces of remarkably thin gilding remain on the statue. It is an ancient technique using a gold-mercury amalgam, which is heated to bond gold to the surface to symbolize nobility.

"The bronze warrior statue has a full, rounded face with long eyebrows, deep-set eyes, a bulbous nose, and slightly pursed lips," Yang said. "Its facial features show the Qin people's bravery and fortitude, allowing modern viewers to feel the warrior's spirit across more than 2,000 years."

As a masterpiece of Qin bronze art, the statue has been exhibited abroad alongside the Terracotta Army in countries like Switzerland, Chile, and Australia.

Liu Xueru contributed to this story.