An early man-made blue pigment from China—barium copper silicate

Barium copper silicate, BaCuSi4O10, an artificially produced mineral, has been identified on Chinese painted ceramic objects attributed to the Han dynasty (208 Bc–220 AD). The mineral has also been observed as an important component in octagonal sticks probably dating to the Warring States period (475–221 BC) or to the Han dynasty. This man-made mineral has been hitherto unreported as a pigment in the ancient Chinese palette.