George Kaufmann brings his pet, Sollie, to his jewellery shop, Robert Bernard Jewellers, in Rockville, Maryland, every day.
Mr Kaufmann and his business partner, Robert Rosin, were meeting a diamond dealer in late January and perusing his gems when disaster struck.
The three men were looking at a 3-carat diamond, valued at $20,000, when the stone suddenly fell to the floor - landing right next to Sollie. Before anyone could retrieve it, the dog ate the gem.
They rushed the animal to a vet, who said nature would have to take its course, so they spent three anxious days waiting to see if the gem would turn up in the dog's stool.
"When we took a walk in the morning and evening I collected and went through everything," Mr Kaufmann said.
"It wasn't glamorous, but you gotta do what you gotta do," Mr Kaufmann told Fox News.
Eventually, his patience paid off, and Mr Kaufmann found the diamond - which he cleaned and returned to the dealer.