It turns out there was a reason for that confusion: the fake diamonds were actually real diamonds. At least, the ones in police custody are.

The case could cause red faces for the International Gemmological Institute (IGI), which had initially flagged the 600 stones as fakes. The police were called, and the stones in question taken as evidence.

According to the Antwerp World Diamond Centre, the IGI did nothing wrong. “The centre uses methods that are 100% reliable and have never been found to be wrong,” said spokesperson Caroline De Wolf. “The only thing I can think of is that the police seized the wrong half of the diamonds.”

Understandable, given that even the experts couldn’t tell fake from genuine. But, if that’s the case, what happened to the fake diamonds that were taken by the trader, while the real diamonds were left behind?

“We’re faced with a riddle,” admitted spokesperson Stéphanie Chomé of the Antwerp police. “Were the diamonds switched or was a mistake made elsewhere? Our investigation continues.”

*On the weekend of 15 February 2003, thieves emptied the strongroom of the Antwerp Diamond Centre and took stones, gold and other booty worth an estimated €75 million, made possible by hiring a tiny office in the building for three years as a front. The robbers were caught when they dumped some rubbish by the side of a quiet road off the E19, which contained a half-eaten sandwich with the DNA of Italian criminal Leonardo Notarbartolo. Rights to a movie based on the event have been secured.