Mark discovered the ring, engraved with images of St Elizabeth of Hungary and the infant Christ, in 2016.
Mark Thompson, who spray paints fork lift trucks, was in the famous Nottinghamshire woodland for just 20 minutes when his metal detector sounded.
The glint of gold caught his attention and he could hardly believe what he unearthedCredit: MarkThompson/BNPS
The ring, which is engraved with an infant Christ on one side and a female saint on the other, is believed to date from the 14th centuryCredit: MarkThompson/BNPS
Mr Thompson shows off his impressive discovery, which could net him between £20,000 and £70,000Credit: MarkThompson/BNPS
The case of the ring has now been referred to a coroner to determine if it is a treasureCredit: MarkThompson/BNPS
The 34-year-old, who had only taken up the hobby 18 months ago, was expecting to find something innocuous.
But as he shovelled the dirt, a glint of gold emerged on ornate piece of jewellery with a precious sapphire.
Auctioneers have since told him that the precious ring could fetch between £20,000 and £70,000.
Mr Thompson said: "I had been out metal detecting with a group for about 20 minutes when I heard the signal.
"I was really excited when I saw that it was gold, but I didn't realise at that point just how significant it might be.
It is believed the ring, which is engraved with an infant Christ on one side and a female saint on the other, dates from the 14th century.
The ring was discovered in the heart of Robin Hood woodland in NottinghamshireCredit: MarkThompson/BNPS
Ms Boughton's report into the ring compares the stone with one used on the tomb of former Archbishop of Canterbury William Wytlesey, who died in 1374.
