Now this is some terrific "structural" color!
Here is the information from Earth and Sky
"This African fruit is called Pollia condensata – sometimes called the marble berry. It’s found growing wild the forests of Ethiopia, Mozambique, Tanzania and other African countries. It has shiny blue berries – said to be hard as a rock – that are mainly seeds. Although it’s called a fruit, it can’t be eaten. In some African nations, the small metallic fruits have been used for decorative purposes because their colors stay intense for many years."