The End of the Silmarilli
Each took a single Silmaril, saying that one was lost unto them and two remained, and but two brethren. But the jewel burned the hand of Maidros in pain unbearable (and he had but one hand as has before been told); and he perceived that it was as Fionwë had said, and that his right thereto had become void, and that the oath was vain. And being in anguish and despair he cast himself into a gaping chasm filled with fire, and so ended; and his Silmaril was taken into the bosom of the Earth.
And it is told also of Maglor that he could not bear the pain with which the Silmaril tormented him; and he cast it at last into the sea, and thereafter wandered ever upon the shore singing in pain and regret beside the waves; for Maglor was the mightiest of the singers of old, but he came never back among the folk of Elfinesse.
"$18 in the Q II version" - "The Quenta" - The Shaping of Middle-earth - HoME - J.R.R. Tolkien
But they took Vingelot, and they hallowed it, and they bore it away through Valinor to the uttermost rim of the world, and there it [added: passed through the Door of Night and] was lifted up even into the oceans of heaven. Now fair and marvellous was that vessel made, and it was filled with a wavering flame, pure and bright; and Eärendel the mariner sat at the helm, glistening with dust of elven-gems; and the Silmaril was bound upon his brow.
"The Conclusion of the Quenta Silmarillion" - The Lost Road and Other Writings - HoME - J.R.R. Tolkien