A 2lb lump of whale vomit - or ambergris to give it its correct name - is to cross the block at Adam Partridge in Macclesfield on September 25.
The incredibly rare material is used in the manufacture of perfume and is said to provide a sensual and musky aroma.
The present lot is valued at £5,000-7,000 ($7,691-10,767). It was found by a dog walker in Anglesey, Wales.
Mr Surfleet, of Adam Partridge auction house in Macclesfield, told Wales Online: "I've never had one like this before at auction. The price received will be dependent on the quality.
"Ambergris is formed in a sperm whale's digestive system and is passed either as vomit or as part of the faeces. Scientists believe it is used to coat irritating objects in the whale's intestines.
"The vendor was walking his dog on a beach in Anglesey when he came across it. He thought it might have some value and got in touch with us."
He also explained that the ambergris smells very strong but "we have a strong-room which is temperature controlled and at the moment it's doing quite well in there."
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