Black opal is a highly sought-after and valuable type of opal known for its dark body tone and vibrant play of colour. The dark background of black opals makes the rainbow hues of the opal's play of colour stand out even more, creating a striking and unique appearance. Black opals are typically found in the Lightning Ridge area of New South Wales, Australia. They are considered some of the rarest and most valuable opals worldwide. They are also considered to be the national gemstone of Australia. Due to their rarity and beauty, black opals are often used in high-end jewellery and are considered a valuable investment.