According to newspaper reports, businessman Jim Sanders found the nugget ten feet underground on his family's Nevada county land using a metal detector.
A chunk of gold that size could be worth more than $100,000 dollars, but some experts say sanders' story sounds fishy.
"If there was a metal detector on Earth that could go down 10 feet for a nugget, I'd buy it," Tom Nicholson from Sierra Nevada Ground Scan said.
Sanders plans to start the permit process for gold mining on his property, even though he could face environmental opposition.
He says he'll offer more information about his find in a few months.