An interesting fact about white opal that sets it apart from other precious gemstones is that the play-of-color often seen in these gems is due to the presence of microscopic spheres of silica gel. When these spheres are stacked in a neat and regular pattern, they diffract light, breaking it up into spectral colors. The size and arrangement of the spheres and voids influence the colors produced, with larger spheres producing reds and smaller spheres producing blues. This intricate natural structure means the color display seen in each white opal is truly one-of-a-kind.
