Precious opal is a unique gemstone known for its vibrant play of colors, which can include shades of red, blue, green, and yellow. This optical phenomenon, called opalescence, occurs due to the microscopic silica spheres within the stone that diffract light. Precious opal is primarily found in countries like Australia, Ethiopia, and Mexico. Unlike other gemstones, precious opal is not transparent but rather displays a milky or translucent appearance. It is often used in jewelry, such as rings and necklaces, and is valued for its beauty and rarity. The stone is also sensitive to temperature and moisture, requiring careful handling to maintain its luster.