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# A Lost Purple Pigment, Where Quantum Physics and the Terracotta Warriors Collide
- URL: https://hyperallergic.com/a-lost-purple-pigment-where-quantum-physics-and-the-terracotta-warriors-collide/
- Published: 2014-12-18T03:45:53.000Z
- Updated: 2025-11-24T16:00:15.000Z
- Description: The connection between contemporary quantum physics and China's ancient Terracotta Warriors is a lost pigment called Han purple. The vibrant hue appeared in the Zhou dynasty and faded out sometime near 220 AD; art didn't see a purple as vivid until 19th-century manufacturing.
- Author: Allison Meier
- Tags: Art, Art History, China, Science, Terracotta Warriors, #wp, #wp-post, #image-position-hidden, #Import 2025-11-24 07:08 (2014, 2015, part 2)

![The Terracotta Warriors in China (photograph by Kevin Poh, via Flickr)](https://storage.ghost.io/c/51/f8/51f871d8-b6be-4a73-b958-0ca4fff0110a/content/images/hyperallergic-newspack-s3-amazonaws-com/uploads/2014/11/terracottawarriorschina.jpg)

The Terracotta Warriors in China (photo by Kevin Poh/Flickr)

The connection between contemporary quantum physics and China’s ancient Terracotta Warriors is a lost pigment called [Han purple](http://en.wikipedia.org/wiki/Han%5Fpurple%5Fand%5FHan%5Fblue?ref=hyperallergic.com). The vibrant hue appeared in the Zhou dynasty and faded out sometime near 220 AD; art didn’t see a purple as vivid until 19th-century manufacturing.

Han purple has strange properties, particularly at low temperature points. Back in 2006, researchers at Stanford, Los Alamos National Laboratory, and the Institute for Solid State Physics [described this phenomenon as a “Flatland.”](http://news.stanford.edu/news/2006/june7/flat-060706.html?ref=hyperallergic.com) When exposed to extremely low temperatures, magnetic waves going through the pigment lose their third dimension. Recently Esther Inglis-Arkell at io9 [returned to this research](http://io9.com/this-2000-year-old-pigment-can-eliminate-the-third-dime-1661476168?ref=hyperallergic.com), explaining:

> At higher temperatures, it propagates like a regular wave, traveling in three dimensions. Get under one degree Kelvin, and it no longer has a vertical component. It propagates in two dimensions only.

This fluctuating state of matter, likely caused by the pigment’s diversely layered barium copper silicate structure, [isn’t seen often](http://www.magnet.fsu.edu/mediacenter/news/pressreleases/2006may31.html?ref=hyperallergic.com). We’ve examined obsolete pigments at Hyperallergic before, whether a [brown made of actual mummies](http://hyperallergic.com/74661/the-colorful-stories-of-5-obsolete-art-pigments/) or [poisonous arsenic greens](http://hyperallergic.com/74922/more-vibrant-tales-of-obsolete-pigments/). Han purple is one of the first known synthetic pigments, and its rarity [made it a powerful color](http://www.asianart.org/collections/han-purple?ref=hyperallergic.com).

This is where the Terracotta Warriors come in, as the Qin dynasty funerary army retains traces of the color (although its hues largely [oxidized after exhumation](http://www.chinadaily.com.cn/china/2010-09/09/content%5F11278335.htm?ref=hyperallergic.com)). Some have speculated that the purple came via the Silk Road, with information from Egypt and its [famous blue](http://en.wikipedia.org/wiki/Egyptian%5Fblue?ref=hyperallergic.com) traveling the distance; however, at *Symmetry*, a particle physics online magazine, [Lori Ann White writes](http://www.symmetrymagazine.org/article/november-2014/ancient-pigments-modern-mystery?ref=hyperallergic.com): “Researchers discovered that Chinese pigment-makers used lead to lower the melting point of the barium in Han Purple, a step not taken in the production of Egyptian Blue.” She goes on to say that glass makers “in ancient China may have stumbled on Han Purple while trying to develop a jade-like glass, a process that also involved lead.”

The peculiar Han purple, sourced from a byproduct and with its two-dimensional properties, may also have a brand new technological purpose: some scientists are looking to the research on it to help inform the process of building [quantum computers](http://www.magnet.fsu.edu/mediacenter/news/pressreleases/2006may31.html?ref=hyperallergic.com).