GENEVA: A tiny Swiss gold coin bearing a picture of Albert Einstein sticking his tongue out has been crowned as the world’s smallest commemorative coin, Switzerland’s mint announced on Tuesday. The miniature coin, with a face value of a quarter of a Swiss franc (27 US cents, 23 euro cents), measures just 2.96 millimetres (0.1 inches) in diameter and weighs only 0.063 grammes (0.002 ounces).