"The earliest sites that have yielded metal objects date to the late fourth and third millennia BCE.〔Linduff 1997:306-418 (Linduff, K. M. 1997. ''An Archaeological Overview: Section 1. Reconstructing Frontier Cultures from Archaeological Evidence'', in: E. C. Bunker, et al., Ancient Bronzes of the Eastern Eurasian Steppes from the Arthur M. Sackler Collections, New
York: The Arthur M. Sackler Foundation, 1997)〕〔Mei 2000 (Mei, Jianjun 2000. ''Copper and Bronze Metallurgy in Late Prehistoric Xinjiang: Its cultural context and relationship with neighboring regions'', BAR International Series 865, Oxford: Archaeopress.)〕 Quite early metal-using communities are found in Qijia and Siba sites in Gansu, with comparable sites in Xinjiang in the west, and others in Shandong, Liaoning and Inner Mongolia in the east and north, and in the Central Plain in the lowest levels at Erlitou."〔Katheryn M. Linduff, Jianjun Mei (2008), (''Metallurgy in Ancient Eastern Asia: How is it Studied? Where is the Field Headed?'' (PDF) ) The British Museum〕

"The Qijia culture (c. 2500-1900 B.C.) of Qinghai, Gansu and western
Shaanxi has yielded copper and bronze utilitarian items and gold, copper and bronze personal ornaments. The earliest dates for metal in this region are found at a Majiayao site at Linjia, Dongxiang, Gansu (KGXB 1981)."〔

"Their dates range from 2900 – 1600 BCE. These metal objects represent the Majiayao 马家 窑 Type of the Majiayao Culture (c. 3100 – 2700 BCE), Zongri 宗日 Culture (c. 3600 – 2050 BCE), Machang 马 厂 Type (c. 2300 – 2000 BCE), Qijia 齐家 Culture (c.2050 – 1915 BCE), and Siba 四坝 Culture (c. 2000 – 1600 BCE)."〔Bai Yunxiang (2003), (''A Discussion on Early Metals and the Origins of Bronze Casting in China.'' (PDF) ) Chinese Archaeology, Vol 3(1)〕