The first is quite tasty: in 1947, Frances Gerety, editor specializing in advertising, planks on a series of delicate orders. She goes to bed when she realizes that she still has an order to honor: a slogan for the large mining group De Beers. Exhausted, she said to herself: "My God, give me an idea." On this vow, she goes to sleep. In the middle of the night, she wakes up and quickly scribbles a sentence that has just crossed her mind. A few hours later, she presents her idea at a meeting. According to her, "no one has jumped for joy" and yet the idea has not only made its way, but has also ensured the glory and supremacy of diamond dealers in the world of jewelery for decades to come. This slogan was: "A diamond is eternal" ("A diamond is forever"). Nothing has been invented since then. The second event is a technical innovation: crimping. In 1886, while fashion was still in heavy decorations and imposing engravings that gagged the brilliance of the stones, Charles Lewis Tiffany imagined a ring on which the diamond was simply elevated by means of six claws in platinum. Few metal, bare stone, as floating, to better spread its fire. The deepest ideas are often the simplest. The American jeweler has just invented the absolute icon of the century to come. An icon so universal that we almost forgot where it came from.