You have been asked to collect black stones for a ritual Gormr has planned for the commemoration of Skorgrím, king of the Dourhands of old, before their fall into obscurity.
'Lord Gormr has told us that you were the one to first discover Skorgrím's body the day the Silver Deep Mine nearly collapsed, when Gormr took his Stewardship. This has earned you a small amount of favour with us, even though your party of Longbeards has come unbidden and unwelcome.
'We are having a commemoration of Skorgrím's many achievements as king of the Dourhands, but we need ritual stones, black as pitch. I was not able to find enough for everyone that plans to attend. They are a form of tribute to Skorgrím-king.
'You should make yourself useful and collect some more. They can be found in and around the Winterheight cave, east of here.'
The ritual stones can be found in and around the Rockbelly Pit, east of the Berghold at Thorin's Gate.
You should collect black stones for the commemorative ritual being prepared by the Dourhands.
Bjarni is at the Berghold in the southern area of Thorin's Gate.
You should speak with Bjarni and give him the black stones you have collected.