How a poor boy from London's East End became the most exclusive diamond merchant you've never heard of.British billionaire Laurence Graff, the man jewelry business insiders call the new Harry Winston, swears this story is true: A woman and her husband walk into Graff's shop on London's swanky New Bond Street and ask to see the stunning diamond-and-ruby necklace in the window. It's the woman's birthday and hubby wants to buy her a bauble. At $2 million, however, he feels the price is too steep. Instead he offers $1 million and exits the store, giving the jeweler 24 hours to cash the check. Later that day the lady returns with a second man, her lover. He, too, admires the necklace but finds the price too high. Another $1 million check is written and left on Graff's desk. The dapper jeweler, ever discreet and always the consummate salesman, breathes no word of the birthday girl's earlier visit to his store. Later she returns once more to scoop up her present, and presumably tells each of her benefactors that he has gotten a bargain from the jeweler. Graff cashes both checks.

It has the flavor of a very tall tale. Why does Graff tell it? It adds to the mystique and drama that define his business, the upper tier of jewelry retailing. The 69-year-old Laurence Graff climbed from scrubbing toilets in a Hatton Garden workshop to the helm of a worldwide brand with 15 stores in the globe's wealthiest spots, from Monte Carlo to Dubai to Moscow. Behind this retail chain is a wholesale buying operation: Graff Diamonds International is vertically integrated, taking stones from the rough shapes that come out of the mine to the display case. He sells stones of the greatest weight and highest quality and claims an average transaction price of $400,000. By that score he seems to easily surpass such classic outfits as Cartier, Winston, Van Cleef & Arpels and Tiffany.