One of the world’s most valuable coins will go under the hammer at Stanley Gibbons Baldwin’s in London this month. Made out of 3.61kg of pure gold, the coin is studded with 6,462 diamonds and is roughly the size of a dinner plate. The coin itself is a decadent and intricate tribute to Britain’s longest reigning monarch, minted by The East India Company. (Image credit: Stanley Gibbons Baldwin's)‘Not only is it a coin, but it's also a piece of art,’ Gladdle told me. Behind him and Carter hung a copy of an Andy Warhol portrait of Queen Elizabeth II.