Pollia condensata, sometimes called the marble berry,[2][3][4] is a perennial herbaceous plant with stoloniferous stems and hard, dry, shiny, round, metallic blue fruit.

It has large, smooth, narrow leaves, and pale pink or whitish flowers on a stem about 60 cm high.

Beneath this glossy surface lies a special layer of cells which have an elaborate but unpigmented microstructure, whose function is to reflect light within a narrow range of wavelengths.

[9] According to materials scientist Ullrich Steiner, who led the team which carried out the original research on structural color in plants, Structural colors come about not by pigments that absorb light, but the way transparent material is arranged on the surface of a substance ... light bounces off the interface ... between each of these layers ...

The brightness and color purity we see in the fruit comes from the fact that many, many layers add up to produce these very strong reflective characteristics of just one wavelength.