A publication of the Archaeological Institute of America

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Purple Reign Volume 60 Number 5, September/October 2007
by Samir S. Patel

How ancient Chinese chemists added color to the Emperor's army

[image] The purple on this terracotta warrior from the tomb of Emperor Qin Shihuangdi in Xi'an is one of only three known synthetic blue or purple pigments in the ancient world. (Courtesy The Museum of the Terracotta Warriors and Horses of Emperor Qin Shihuang)

Purple is special. Throughout antiquity, the color was a mark of wealth, aristocracy, and royalty, in large part because it was so rare. Prior to the nineteenth century, when modern production methods made synthetic pigments common, there were only hugely expensive purple dyes, a couple of uncommon purplish minerals, and mixtures of red and blue, but no true purple pigment--except during a few hundred years in ancient China. The Chinese of the Qin and Han dynasties (221 B.C.-A.D. 220) used a mysterious lavender shade to decorate pottery and some of the famous terracotta warriors in the tomb of Emperor Qin Shihuangdi in Xi'an. This pigment, known as Han or Chinese purple, was a technological wonder, a complex synthetic compound made before the invention of paper or any codified understanding of elemental chemistry. How the ancient Chinese created this color, and the chemically related Han or Chinese blue, has puzzled scientists since the pigment was rediscovered in the 1990s. Did the Chinese stumble across the intricate formula, or did they have a little help from the other side of the world? And why did the pigment disappear entirely at the end of the Han Dynasty?

Samir S. Patel is an associate editor at ARCHAEOLOGY.

© 2007 by the Archaeological Institute of America