Some chemists at the University of Georgia (US) have analyzed the blue pigment found in Egyptian monuments and elsewhere to discover that it has some unique properties at the nanoscale which ancient Egyptians and others capitalized on in their artworks. From the Feb. 20, 2013 news item on Nanowerk,

Tina T. Salguero [University of Georgia] and colleagues point out that Egyptian blue, regarded as humanity’s first artificial pigment, was used in paintings on tombs, statues and other objects throughout the ancient Mediterranean world. Remnants have been found, for instance, on the statue of the messenger goddess Iris on the Parthenon and in the famous Pond in a Garden fresco in the tomb of Egyptian “scribe and counter of grain” Nebamun in Thebes.

They describe surprise in discovering that the calcium copper silicate in Egyptian blue breaks apart into nanosheets so thin that thousands would fit across the width of a human hair. The sheets produce invisible infrared (IR) radiation similar to the beams that communicate between remote controls and TVs, car door locks and other telecommunications devices.

The article can be found here,

Nanoscience of an Ancient Pigment by Darrah Johnson-McDaniel, Christopher A. Barrett, Asma Sharafi, and Tina T. Salguero. J. Am. Chem. Soc., 2013, 135 (5), pp 1677–1679 DOI: 10.1021/ja310587c Publication Date (Web): December 10, 2012

Copyright © 2012 American Chemical Society

The article is behind a paywall but the abstract is open to everyone and there is this image,

If I understand this rightly, Egyptian blue can be categorized as both a traditional pigment and a structural color due to nanoscale structures. (I recently wrote about structure, color, and the nanoscale in a Feb. 7, 2013 posting.)

As these things do from time to time, it reminded me of a song,

Enjoy!