Synthetic or natural? Diamond ring hunters may soon be asking themselves this question, as technological advances mean the gemstone market could be poised for a flood of man-made stones. Presenter Justin Rowlatt visits the new research headquarters of Element Six, the synthetics arm of mining giant de Beers, to find out how they are made and their proliferating industrial uses. He hears from diamonds journalist Chaim Even Zohar about the factory-made diamonds fraudulently passed of as natural gems. Author Matthew Hart retells the yarn of how a lowly small-time prospector first broke the de Beers cartel. And we hear from de Beers itself - their marketing head Stephen Lussier explains why diamonds really are forever.