Opal flashes colors as the stone moves. This phenomenon is called play-of-color and no two opals are exactly alike. Opals are cut and polished into cabochons to best feature their unique display. Keep your opal looking its best by cleaning in warm water with dish soap. Gently scrub with a clean, soft toothbrush. Rinse in warm water and pat dry. Store individually in its pouch to prevent scratching.