Chinese Purple

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The PBS program “Secrets of the Dead: China’s Terracotta Warriors” explores the creation of an army of 8,000 clay soldiers that were buried with the first emperor of China. Although they have faded over time, the soldiers were originally painted in bright colors, including Chinese purple. Chinese purple is a man-made color and is very similar to Egyptian blue, except that it contains lead oxide and barium instead of calcium. The scientists on the PBS program believe that the two civilizations created their pigments independently and that Chinese purple was developed for religious purposes.

Around the time that the clay soldiers were made, over 2,000 years ago, the Chinese elite paid alchemists to find a formula to make jade. Jade was prized, because it was believed to magically protect the wearer and grant them longevity, even immortality. Bodies were sometimes buried in jade suits and emperors drank elixirs made with powdered jade. In their attempt to replicate the immortality stone, alchemists created Chinese glass, which looks like jade and is made with barium and lead. In fact, the chemical compositions of Chinese glass and Chinese purple are nearly identical, which supports the idea that the pigment was created by alchemists as they struggled to make jade.

In 2006, scientists at Cambridge University studied Chinese purple by placing a few flakes of it into the core of a powerful magnet. They observed that the molecules of Chinese purple became a single magnetic wave. When it was cooled down to hundreds of degrees below zero, the magnetic wave lost its third dimension. Scientists believe this discovery can help them make better superconductors (materials that conduct electricity with no resistance).