Chinese Purple - Ancient Pigment of the Terracotta Soldiers

Purple Pigment of the Terracotta Soldiers

Terracotta Warriors of Qin Huangshi, Painted with Chinese Purple
Terracotta Warriors of Qin Huangshi, Painted with Chinese Purple. Billy Hustace / Getty Images

Chinese Purple, sometimes known as Han Purple, was a manufactured pigment used by ancient Chinese cultures between at least 800 BC and 220 AD, and it was the first manmade purple pigment created in ancient China. Its most famous use was on the terracotta soldiers of the Qin dynasty emperor Qin Shuangdi.

Chemistry of Chinese Purple

Han purple is a manufactured compound based on barium-copper silicate, and the purple color derives from the red impurities in copper oxide.

Its chemical definition is BaCuSi2O6. The definition of Han blue, a similar pigment but containing added azurite, is BaCuSi4O10).

Under polarised light, Chinese purple changes color, due to the optical property known as pleochroism. The color varies from dark to light purple hues but can range towards colorlessness.

Uses and History of Chinese Purple

As with the other blue pigments developed by the Chinese such as Han Blue and Han Ultramarine, Han Purple has been found in beads dated to the Western Zhou dynasty beginning about 800 BC. The earliest known Han purple, blue and aquamarine octagonal sticks--compact bodies made of the pigment and thought to represent pigment crayons--date to the Eastern Zhou period (770-221 BC), and are found during the Qin and Han dynasties (220-207 BC and 206 BC-220 AD) as well.

In terms of popularity, the use of Chinese Purple in beads and colored paintings increased during the Warring States Period (475-221 BC), and saw a boom in use in the Qin and Western Han dynasty.

Not only was the purple used as a pigment on the coats of Emperor Qin's terracotta army, but it was also extensively used in beads and earrings, and in murals painted on the walls of Han dynasty tombs. By the Eastern Han dynasty, the use of the pigment dropped off, presumably because of production techniques and artistic preferences.

The use of Han purple in making lead-barium glass beads led to the additive of lead in the pigment itself: the combination serves as a catalyst to accelerate the decomposition of the barium and so require lower production temperatures, and to act as fluxes.

Tao and the Color Purple

Using historical records, a research team led by Zhi Liu has argued that the color was invented by Taoist alchemists to imitate jade, an important substance for the Taoist religion. Cullen, however, believes that the historical reference to the Tao (or Dao) is not necessarily a reference to the Taoist religion, but instead refers to a wide range of secular knowledge and philosophy.

Liu points out that the use of jade in burials was banned at the end of the Han Dynasty by the Emperor Wen, along with other conspicuous consumption traits of the Han and Qin dynasties, as epitomized by the Emperor Qin's tomb.

However that happened, by the Eastern Han period, Han purple was no longer used, and over the centuries, the recipe for Chinese purple was lost. Modern day chemists armed with high-resolution transmission electron microscopy, electron energy loss spectroscopy, and x-ray microanalysis, have been able to reconstruct reasonable facsimiles.

Sources

This article is a part of the About.com guide to the Ancient Pigments, and the Dictionary of Archaeology.

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Berke H, and Wiedemann HG. 2000. The Chemistry and Fabrication of the Anthropogenic Pigments Chinese Blue and Purple in Ancient China. East Asian Science, Technology, and Medicine 17:94-120.

Cullen C. 2008. Taoism (Daoism) and ‘Chinese Purple’: a note on some historical issues. Journal of Archaeological Science 35(7):2074-2076.

Jin P, Wang T, Ma M, Yang X, Zhu J, Nan P, and Wang SU. 2012. Research on the pigments from painted ceramics excavated from the Yangqiaopan tombs of the late Han Dynasty (48 BC – AD 25). Archaeometry 54(6):1040-1059.

Li M, Wang J, and Ma Q. 2015. The effect of lead additives on ancient Chinese Purple pigment synthesis.

Journal of Cultural Heritage 16(4):575-578.

Liu Z. 2008. Reply to “Taoism (Daoism) and ‘Chinese Purple’: a note on some historical issues”. Journal of Archaeological Science 35(7):2077-2078.

Liu Z, Mehta A, Tamura N, Pickard D, Rong B, Zhou T, and Pianetta P. 2007. Influence of Taoism on the invention of the purple pigment used on the Qin terracotta warriors. Journal of Archaeological Science 34(11):1878-1883.

Wei S, Ma Q, and Schreiner M. 2012. Scientific investigation of the paint and adhesive materials used in the Western Han dynasty polychromy terracotta army, Qingzhou, China. Journal of Archaeological Science

Xia Y, Ma Q, Zhang Z, Liu Z, Feng J, Shao A, Wang W, and Fu Q. 2014. Development of Chinese barium copper silicate pigments during the Qin Empire based on Raman and polarized light microscopy studies. Journal of Archaeological Science 49:500-509.

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Hirst, K. Kris. "Chinese Purple - Ancient Pigment of the Terracotta Soldiers." ThoughtCo, Aug. 9, 2016, thoughtco.com/chinese-purple-pigment-terracotta-soldiers-171275. Hirst, K. Kris. (2016, August 9). Chinese Purple - Ancient Pigment of the Terracotta Soldiers. Retrieved from https://www.thoughtco.com/chinese-purple-pigment-terracotta-soldiers-171275 Hirst, K. Kris. "Chinese Purple - Ancient Pigment of the Terracotta Soldiers." ThoughtCo. https://www.thoughtco.com/chinese-purple-pigment-terracotta-soldiers-171275 (accessed December 13, 2017).