The Tampa Woman's Club held a fundraiser over the weekend where they poured 400 flutes of champagne.
For USD 20, members could buy a flute of champagne and a chance to win a one-carat, USD 5,000 diamond.
Each flute contained a cubic zirconia stone, and only one of them contained the prized gem donated by Continental Wholesale Diamond, ABC News reported.
After patrons finished their drinks, the real diamond was nowhere to be found.
The elderly woman then came forward and said she accidentally swallowed what was in her flute.
"We were laughing and I wasn't paying attention and I took a swallow," said Miriam.
Miriam immediately went to an area hospital for an x-ray only to find out diamonds don't show up on x-ray. She went in for a routine colonoscopy the very next day, where her doctor ended up finding the elusive diamond.
"We still had to find out if indeed that was the winning diamond," Miriam said.
Miriam stopped by the jewelry store on her way home to have the diamond tested, the report said.
Once the diamond was washed and then steamed it was tested and it turned out to be the prized diamond.
Miriam has decided to keep the diamond in her family.