Editor's note: The ancient Greeks and Romans valued opals, believing they warded off bad luck and negativity. More importantly, it’s the birthstone of the world’s most fabulous people: October babies! The opal’s ability to change color as it absorbs light and moisture makes it one of the most interesting, popular, and sought-after gemstones in the world. Your screens deserve to get in on some of this beauty, don’t you think? Get a cool Opal wallpaper today!