How a gold nugget ended up in the Shropshire Hills, near Much Wenlock, remains a mystery.
The area is an ancient landscape once under a prehistoric ocean and hunters often find remnants of coral in the area.
There was also a large amount of rock that originally came from Wales, in which gold and copper were mined extensively during the Bronze Age.
Mr Brock’s discovery was made on a site believed to have been an old track or road with railway lines running through, containing stone possibly distributed from Wales.
The only previous bigger examples in Britain have been found in either Wales and Scotland.
The Douglas Nugget found in Perthshire weighed 85.7g, another from the shores of Anglesey weighed 97.12g and The Reunion Nugget found in Scotland in 2019 weighed 121.3g.
Mullock Jones, the auctioneer, is offering the nugget for sale in a timed auction which began last weekend and runs until April 1. The nugget is estimated to sell for £30,000.
Mr Brock has said he will split the proceeds of the auction with the land owner.