The Governor of Zimbabwe’s Reserve Bank told a conference that 10,000 people were entering Zimbabwe each month to traffic in illegal diamonds. 

From The Herald (via AllAfrica.com):

Over 10 000 people from all over the world are visiting the eastern border town of Mutare every month for illegal activities involving diamonds, Reserve Bank of Zimbabwe governor Gideon Gono said Wednesday.

Gono told a conference of exporters that there were over 2 000 syndicates in the town that were smuggling diamonds out of the country

Diamond Smuggling is a $280 million market ranked 39th on the Havocscope Black Market Contraband Index.