Action News was there as the victim explained Tuesday night to police what had just happened moments earlier.
The 44-year-old man tells detectives he was just leaving Jewelers Row around 6:00 p.m. when two men at 11th and Sansom streets made off with his bag.
He tells police inside the bag was $348,000 worth of diamonds.
Police say the victim describes the suspects as wearing a red jacket and the other in a black jacket and brown hat.
A police source says the victim is from out of the country and is allowed to show diamonds in the US, but does not have a license to do business.