Boulder Opal

Boulder opal is a precious opal variety unique to Queensland, Australia, in which a thin seam of play-of-color opal forms within ironstone or sandstone host rock and is left attached to enhance stability. The dark brown ironstone backing intensifies the opal's spectral fire, and the natural matrix creates one-of-a-kind patterns that may mimic landscapes, forests, or abstract paintings. Because the opal layer is often paper-thin, the backing is essential rather than decorative.