Opals are a mineraloid, an amorphous material without a crystalline structure. Opals are composed of tiny spheres of amorphous silica. These spheres are all the exact same size and arranged in a perfect, repeating pattern. In this perfect environment, they will diffract the passing light into its component colors. As the light exits the opal, it displays this incredibly beautiful rainbow-effect that opals are known for. Opal usually forms from low temperature deposition from groundwaters in cavities in sedimentary and igneous rocks.
Opals are the traditional October birthstone. There has become somewhat of a superstition of it being bad luck for someone who was born in another month to wear an Opal but this is actually originating from a novel written in the 1800s. Historically, many ancient cultures all over the world believed Opals to hold magical powers and was believed to be the most lucky of all stones! Anicent Grecians believed Opals gave their owners the gift of prophecy and protection from disease. Precious Opals are one of the most magical gems!