Chow Cheng, 32, was arrested after allegedly swallowing a diamond worth almost $14,000 at Sri Lanka’s largest international gem and jewellery exhibition last Wednesday.
Cheng and another man were inspecting diamonds at an trade stand when the exhibitor, Suresh Christopher Wijekoon, noticed Cheng was attempting to switch the stone with a synthetic stone. It is alleged Cheng swallowed the 1.5-carat diamond when he realised his ruse had been discovered.
Cheng was taken to hospital and given laxatives to help remove the diamond, however x-rays later revealed the diamond had lodged in his throat.
Doctors then advised surgery to remove the diamond, with Associated Press reporting the man’s life could potentially be in danger.
"Doctors have advised surgery to remove the diamond," police spokesman Ajith Rohana told AFP.
"The man's life could be in danger if the pointed end of the diamond tears his guts. We have already informed courts about this. For the man's own safety, he will have to undergo surgery."
The other man with Cheng at the time of the attempted theft is believed to have been acting as a distraction and immediately fled the scene when Wijekoon raised the alarm.
Wijekoon said he was not certain that the stone Cheng is believed to have swallowed was the natural diamond and it was possible he swallowed the synthetic, with tests to be carried out once the stone is recovered.
Police say a successful prosecution would be dependant on the retrieval of the stone.
It is not the first case of this nature this year, with arrests in Canada and America earlier this year for similar offenses.
It is a dangerous practice, with studies saying around 35 per cent of sharp objects that are ingested, such as diamonds, face complications when passing through the digestive system.