Andvaranaut
Andvaranaut (Andvari’s ring) In Norse mythology, a magic ring belonging to the dwarf Andvari, stolen by the fire-trickster god, Loki. The ring was given to Hreidmar, king of the dwarfs, in part restitution for the murder by Loki of Hreidmar’s son Otter. Andvari, however, cursed the ring so that it would destroy all who came in contact with it. ( And the curse worked–it caused the maiden Brynhild to kill herself when her lover Sigurd gave her the ring as a gift (she became convinced Sigurd had betrayed her). It also caused Fafnir to slay his own father Hreidmar in greed to protect his treasure. Fafnir later used the ring's power to turn himself into a dragon to guard this treasure. )
In Germanic mythology and in Richard Wagner’s works, the ring belongs to Alberich, another name for Andvari. Alberich appears in Wagner’s music dramas Der Ring des Nibelungen, which have to do with the magic ring and the tragedy it brings on all who possess it. He also is portrayed by Arthur Rackham in his illustrations for Wagner’s Ring Cycle.
Main Source : The Encyclopedia of World Mythology and Legend, Third Edition – Written by Anthony S. Mercatante & James R. Dow – Copyright © 2009 by Anthony S. Mercatante