“There's nervousness, there's apprehension,” says mining boss William Lamb, standing in Sotheby's showroom on Bond Street in London. “There's nothing we can do now.”
     Two metres behind him, the biggest diamond on the planet is slowly rotating in its display case. Lamb's company, Lucara Diamond, pulled the 1,109-carat whopper out of its mine in Botswana last year. It is by far the largest diamond ever to go under the hammer and bidding begins in twenty minutes.
     Buyers have had ample time to inspect the stone, Lamb says, with four-hour viewing sessions in every major diamond capital, from Hong Kong to Geneva. Royalty has also been through, marvelling at the size of the stone, which resembles a broken perfume bottle. “Of

course we have a reserve,” Lamb says.
     At the back of the room, Swedish mining billionaire Lukas Lundin, Lucara's chairman and founder, is politely saying hellos. “How are you feeling?” “Earlier, cool as a cucumber.”
     The dimmed lights are turned up bright and everyone is kettled to their seats. Lukas Lundin is in the third row with a white bidding paddle, “109”, William Lamb directly behind him. To warm up the room, Sotheby's auctions off three diamond fragments for charity. A ten-year-old sitting next to his father finds himself bidding against Lucara's chairman, who is putting up his paddle so competitively that he is reprimanded by the auctioneer for bidding against himself. Yet he is never the final bidder. “Sold to the young man on the aisle for $46,000.”

     The charity auction tails off and David Bennett, Sotheby's global head of jewellery, introduces Lucara's huge diamond. “I have seen grown men with tears in their eyes,” he says.
     A bank of thirty Sotheby's staff are lined up behind the telephone desk, but there are empty seats in the main room. Lamb's former colleagues from De Beers, who have risen to senior posts across the diamond industry, are nowhere to be seen. Nor is Laurence Graff, the London-based jeweller who famously bought up every lot at the first tender of pink diamonds from the Argyle mine in Australia. “Unfortunately, we won't be attending the Sotheby's auction,” another non-attendee says, “but we'll be watching it with interest.”
     Bidding opens in US dollars at $50m, with