The mighty giant Hrungnir challenges Þórr to single combat; in the duel Þórr hurls Mjölnir and Hrungnir hurls his whetstone, the hammer shatters the giant's stone head but a shard of the whetstone lodges in Þórr's forehead and the sorceress Gróa tries to sing it out.
Hrungnir átti hest þann er Gullfaxi hét. Hann reið eptir Óðni inn í Ásgarð. Þórr kom til ok vildi berja hann, en Æsir sögðu at hann var í griðum þar. Hrungnir varð þrekkinn ok sagðist munu ríða Ásgarð ofan ok drepa alla Æsi nema Freyju ok Sif. Þórr reiddist ok stefndi honum til einvígis á Grjótúnagarðar.
Hrungnir owned a horse named Gullfaxi. He rode after Odin into Ásgarðr. Þórr arrived and wished to strike him, but the Æsir said he was there under their protection. Hrungnir became insolent and declared he would ride Ásgarðr into ruins and kill all the Æsir save Freyja and Sif. Þórr grew angry and challenged him to single combat at Grjótúnagarðar.
Hrungnir hafði hjarta er var gert af steini, þríhyrnt og hvast. Skjöldr hans var ok steininn. Hann hafði þar brýnstein mikinn á öxlinni. En Þórr kastaði Mjölni á hann ok Hrungnir kastaði brynsteninum. Þeir mœttusk á lofti. Brynssteinninn brast í sundr. Annarr hluti féll á jörðina ok eru þaðan af allar brynisteinar. En Þórr kastaði hamrinum ok lamdi höfuð Hrungnirs.
Hrungnir had a heart made of stone, three-cornered and sharp. His shield was also of stone. He carried a great whetstone on his shoulder. Þórr hurled Mjölnir at him and Hrungnir hurled the whetstone. They met in the air. The whetstone broke apart. One part fell to the earth, and from it come all whetstones. Þórr hurled the hammer and smashed Hrungnir's head.
Skaldic quotations
Þjóðólfr ór Hvini: Haustlöng 14
Þá varð Hrungnir hneigðr, ok hlaut fyr hamri kynnum hroðrs at hníga.
Then Hrungnir was felled, and he had to fall before the hammer, the famed weapon's known powers.