There is a chamber, high in Blackrock Spire, that was once called the Hall of Fortune.  It was where the Dark Iron dwarves kept their relics, trophies and objects of art.$B$BThat was long ago.  It is said the hall has collapsed and is now used for... less savory tasks.  But I believe some old dwarven relics may still be found there.$B$BOne such relic is Doomrigger's clasp, with a surface so encrusted with rare gems that it was said to make weep any dwarf who gazes upon it.$B$BThat clasp, $N, is your goal.