With all we know about gems and the millions upon millions of years it takes to create them, one gem still escapes understanding. The opal. Exactly how an opal is formed cannot be fully explained by science, and that’s one reason why they fascinate us so.
The first thing you notice about an opal are the colors. Not just some colors. Absolutely every color imaginable. As you move and turn an opal, iridescent colors shift from red, green, blue, yellow, purple, and any other color you can imagine. Jewelers call this an opal’s “play-of-color.” This is caused by light diffraction, like how a prism will split white light into all the colors of the rainbow.