Apparently some butterfly wings contain photonic crystals! Evolution figured out how to make them. Even better: the crystals apparently contain defects that make some of the colours more brilliant! https://www.anl.gov/article/xrays-reveal-the-photonic-crystals-in-butterfly-wings-that-create-color#:~:text=This%20structure%2C%20and%20the%20irregularities,%E2%80%9Csparkle%E2%80%9D%20of%20the%20wings.&text=We've%20long%20known%20that,create%20that%20distinctive%20iridescent%20look ….pic.twitter.com/c14MivNRC7
