"Elros and Elrond were taken captive, but Elwing with the Silmaril upon her breast had cast herself into the sea. Thus Maedhros and Maglor gained not the jewel; but it was not lost. For Ulmo bore up Elwing out of the waves, and he gave her the likeness of a great white bird, and upon her breast there shone as a star the Silmaril, as she flew over the water to seek Eärendil her beloved."
— J.R.R. Tolkien, The Silmarillion: "Of the Voyage of Eärendil and the War of Wrath"