The Largest Opal Ever Found

The largest opal in the world was found in Australia in 1956. The 17,000 carat (3450 g/121.7 oz/7.6 lbs) opal was found at a depth of 9.1 metres (30 ft) at the 'Eight Mile' opal field near Coober Pedy, South Australia. This beautiful stone was named Olympic Australis, in honour of the Olympic Games that were held in Melbourne, Australia, that year.

Olympic Australis is 280 mm long, 120 mm thick, and 115 mm wide (11 inches long, 4.75 inches thick, and 4.5 inches wide). It consists of 99% gem opal with an even colour throughout, and has been left in a natural state, unpolished and uncut. The opal is kept in Sydney, and was valued at $2,500,000 in 1997.

Source: Wikipiedia