§ Of the Flight of the Noldor The Silmarillion

In his right hand Morgoth held close the Silmarils, and though they were locked in a crystal casket, they had begun to bum him, and his hand was clenched in pain; but he would not open it 'Nay!' he said. 'Thou hast had thy doe. For with my power that I put into thee thy work was accomplished. I need thee no more. These things thou shalt not have, nor see. I name them unto myself for ever. '