§ Of the Return of the Noldor The Silmarillion

Now on a time Finrod and Galadriel his sister were the guests of Thingol their kinsman in Doriath. Then Finrod was filled with wonder at the strength and majesty of Menegroth, its treasuries and armouries and its many-pillared halls of stone; and it came into his heart that he would build wide halls behind ever-guarded gates in some deep and secret place beneath the hills. Therefore he opened his heart to Thingol, telling him of his dreams; and Thingol spoke to him of the deep gorge of the River Narog, and the caves under the High Faroth in its steep western shore, and when he departed he gave him guides to lead him to that place of which few yet knew. Thus Finrod came to the Caverns of Narog, and began to establish there deep halls and armouries after the fashion of the mansions of Menegroth; and that stronghold was called Nargothrond. In that labour Finrod was aided by the Dwarves of the Blue Mountains; and they were rewarded well, for Finrod had brought more treasures out of Tirion than any other of the princes of the Noldor. And in that time was made for him the Nauglamír, the Necklace of the Dwarves, most renowned of their works in the Elder Days. It was a carcanet of gold, and set therein were gems uncounted from Valinor; but it had a power within it so that it rested lightly on its wearer as a strand of flax, and whatsoever neck it clasped it sat always with grace and loveliness.