In SA 750 a group of Noldor from Lindon led by Celebrimbor settled in Eregion near Khazad-dûm (Moria). Interested in the making of crafts and jewels, they drew close to the Dwarves of Moria and worked with in them in an alliance of friendship and peaceful commence. Only Feanor surpassed this group in cunning for things wrought. Celebrimbor was the most skilled of this group. Their chief city was Ost-in-Edhil which stood in ruins for ages to come. For hundreds of years they prospered and grew immensely wealthy, but Sauron ever hungry for dominion over Middle-earth was jealous of their power. He approached them in SA 1200 disguised as Annatar and the Noldor ever eager for more knowledge, accepted his gifts and instruction. They also followed him because although they loved Middle-Earth they wanted to have the Bliss of Valinor. They could do this with the skills they would learn from this Annatar and make the land of their exile as beautiful as Eressea. With this new Knowledge, they forged the Rings of Power with Celebrimbor alone forging Three Rings. However, in SA 1590 the smiths found themselves betrayed and deceived when Celebrimbor discovered that Sauron forged the One Ring to rule all the others. Celebrimbor then hid his Three Great Rings and Sauron grew angry. He demanded their return and soon declared war on them and in SA 1695. By SA 1697 Eregion was destroyed and Celebrimbor was slain along with many of his Jewel-smiths. Some of the Gwaith-i-Mírdain were evacuated to Rivendell with the help of Elrond. They may have survived into the Third Age there and could have been the makers of Andúril, the new sword of Aragorn II Elessar.
Gwaith-i-Mírdain is a Sindarin word meaning 'People of the Jewel-smiths'.