And this is why most precious stones are placed behind glass, because you never know when some random stranger might just decide to reach out for an impromptu snack.

According to
Yahoo! UK, the incident involving a Chinese man took place at a gem exhibition in Sri Lanka's capital. Exhibitor Suresh Wijekoon who owned the diamond said the man had been behaving suspiciously at his stalls.
When Suresh approached the suspect, the man suddenly swallowed the diamond he had in his hand before police could be alerted. The diamond that was swallowed weighed about 1.5 carats, and is worth an estimated 1.8 million Sri Lankan rupees ($13,636).
The suspect, a 32-year-old from China named Chau Wan, and was taken by
police to a hospital, where an X-ray showed the $13,000 stone inside
him. He is in custody pending further investigation. All we can say is that we wouldn't want to be the guard in charge of watching this guy's bowel movements.