The piece has now been identified as coming from the Mesolithic era and is believed to have been used as a type of sharp weapon, possibly for spearing fish.
Samuel, 11, and a pupil at President Kennedy School, had been out with his dad at their allotment in Watery Lane, Keresley, when they made the discovery.
“I just saw it sticking out of the ground when my dad was digging.
"We picked it up and looked it up on the internet,” Samuel said.
“We sent the photo off and they confirmed it was from the Mesolithic era. It made me feel very happy and I’d like to find more.”
Samuel and his dad Allan, of Hallbrook Road, are involved with the Coventry and District Archaeological Society, in particular the group’s Coventry Historic Environment Project looking into areas in the Allesley, Coundon and Keresley areas.
Allan, 37, sent the photo of the flint off to the group who confirmed it was carved about 10,000 years ago.
“It’s amazing to think this was chipped away by a man all those thousands of years ago,” he said.
“Flint doesn’t occur naturally in Warwickshire so it would have been brought here.”
Allan, who works as a quality engineer at Coventry Press Works, thinks the find is further proof that a large part of greenbelt land near his home should not be used for housing.
The council has earmarked the area as a possible site to build thousands of new homes as part of its government target to build 33,500 homes in and around Coventry.
A recent report has found there are numerous undeveloped areas which could contain important archaeological sites.
These include a medieval manor, believed to be underneath a farm, and a former burial ground or castle.
Allan said: “I’d like to see more investigation of the area.
"There is a lot of history in this area and I think it’s very important this is explored rather than just building homes on top of it.”