What does a Opal rock look like?

Opal is a unique gemstone that typically exhibits a play-of-color, displaying vibrant flashes of various hues, including red, blue, green, and yellow, as light interacts with its internal structure. The stone can appear translucent to opaque and often has a smooth, rounded surface. Common opal types include white, black, and boulder opal, each showcasing different backgrounds and patterns. Its overall appearance can range from a milky or cloudy look to a more vivid, iridescent effect depending on the quality and type of opal.