Most people who enter Downing St bearing a lump of rock find themselves at Horseferry Road Magistrates' Court the next day, but today will see a much-feted exception.
President Sebastian Pinera of Chile plans to visit No 10 and present Prime Minister David Cameron with a souvenir piece of diorite from the depths of San Jose mine which has transformed his country's reputation.
Few official visits have been better timed. Until last week, Chile was, for all but the world's industrial copper consumers, a relatively minor wine producer and exotic holiday location.
But today, Pinera will meet the Prime Minister and the Queen as the man who represents the most uplifting human achievement of recent years.
A Harvard-educated billionaire, Pinera has brought a second rock for the Queen, after an invitation to meet her was added to his schedule at the last minute. He said he had brought "many presents" for Cameron and the Queen, including a copy of the first message the miners sent to the surface.
Back home, some of the miners are now saying they are not prepared to share parts of their story.
"We are not going to talk about that," said 63-year-old Mario Gomez, the oldest of the workers stuck for more than two months in the northern Chilean copper and gold mine, when asked about the nightmare experience.
"That's reserved," was the answer to the same question from Ariel Ticona, 29. Whether this is because of the natural reserve of the working man, or the imminence of book, film and television deals, is not clear.
Rescued miner Victor Segovia took notes which could become the basis for a book about the experience.
Ticona said: "We are going to publish a book."