Large Australian black opal - The Pacific - is expected to sell for more than $700,000 at an auction in Sydney later this month.
Weighing in at 443.56 carats, it was once the largest black opal in the world, earning itself a place in the Guinness Book of World Records in 1990.
The opal is named after the Pacific Ocean due to its size and colour and remains the largest, polished, solid-form black opal to this day.
The Pacific will be sold by the man who found it, Lightning Ridge opal miner Gerald O'Brien, at the Noble Numismatics sale at the State Library of NSW.
The opal is just one of many items up for grabs at the auction which is set to be one of the largest of its type ever held in Sydney.
Approximately 4700 lots will go under the hammer, with The Pacific joining other items such as rare modern and ancient coins in gold, silver and bronze, historical medals, military medals and militaria, stamps, antiquities and artefacts, jewellery, and historical documents.
The auction will begin on November 24.