Growing “Metallic Wood” to New Heights: Radically Decreasing a Material’s Density Without Sacrificing Strength

"The precise spacing of these gaps not only gives metallic wood the strength of titanium at a fraction of the weight, but unique optical properties. Because the spaces between gaps are the same size as the wavelengths of visible light, the light reflecting off of metallic wood interferes to enhance specific colors."

https://scitechdaily.com/growing-metallic-wood-to-new-heights-radically-decreasing-a-materials-density-without-sacrificing-strength/