Hummingbird feathers are irridescent, and many colors. Blues, greens and hints of purple. In other things in nature, blue-green shimmery colors show up.
Butterfly wings, and some beetles, have a sheen to them, that shows their glistening color in the light. Refracting and reflecting back the light that lands on them. Dragonfly wings have that look.
Very ancient japanese porcelain vases and cups used for the tea ceremony have that characteristic too, of translucence. The play of light on the surface, the color like the sky or deep pure water. The light goes through the crackled glaze, bounces off the whiteness of the porcelain clay body underneath, and goes back to your eye, making the porcelain surface appear to glow with an internal colored light.
These little heart shapes are more color test tiles, deliberately sanded and buffed with wear, to bring out the light and sheen.
The newest colors. The elusive, transient colors.
Azure, like the ocean in the tropics.
Like the sky after a rain storm.