blood diamond
n.— «The international diamond industry sought to put the sparkle back into its image Wednesday, adopting strict new measures to stop rebel groups who trade gems for guns to fight some of Africa’s most vicious civil wars.…The industry promised severe penalties for dealers who break the rules and buy or sell so-called “blood diamonds.”» —“New Rules Target ‘Blood Diamonds’” by Antwerp, Netherlands CBS News July 19, 2000. (source: Double-Tongued Dictionary)
I’m pretty sure this phrase was used on a History Channel show too…my guess is “Modern Marvels: Diamond Mining” but I can’t really remember.