Record: The Largest And Most Valuable Opal
In 1956, the largest and most valuable opal in the world was found at the Eight-Mile opal field, in the mining town of Coober Pedy in South Australia. It was discovered at a depth of 9.144 meters (29 feet,) and was named the Olympic Australis opal, due to the Olympic Games being held in Melbourne at the time. It weighs a remarkable 17,000 carats (3450 grams,) and is 99% gem quality.
In 2005, the Olympic Australis was valued at AUD $2.5 million. Due to the purity of the jewel, it has been estimated that over 7,000 carats could be cut from the rough stone but, since the rock is so unique, it will be left in its natural organic state. Currently, the Olympic Australis is kept in Melbourne, at the offices of Altmann & Cherny Ltd.