Most of us think of those celestial stones with fiery colors when we think of opal. However, to be classified as an opal it means that the crystalline structure is spherical instead of geometric. Common opal doesn't have the fire, but it does have a beauty of its own. This opal actually replaced petrified wood hundreds of thousands of years ago! The colors range from soft pastels to the deepest aqua blues. You may even see glints of copper streamers in some cases, and even some dendritic formations! Either way, it is all beautiful!