This shows reflection, refraction but the color comes from diffraction of a sort. The magic ball is a bead of opal, about 12mm across. Inside this mysterious stuff are microscopic speheres of silica, spaced "just so" or then again "just so". The compactness and size of the miniature beads determines which color of light to reflect. That is how opal gems work, in the simple explanation. White light goes in and blue comes out..or red..or green..or yellow. Nature did a neat job with these gems.