Oh go on then...
Having more or less finished work and Xmas shopping...
Cool riddle by the way PW, I'm hoping its a little metaphorical...
Daggers wrenched from owner's hold - dangerous items taken from their owners (hold being hands or caverns I guess)
Dearer bought than jewels or gold - more valuable indeed
Seed of hatred, gift of scorn - caused much trouble, poisoned gifts
Still we sting, a wreath of thorn - still causing heartache
So is the the seven rings of the Dwarves?
All reclaimed by Sauron, very valuable, caused dissention and conflict by increasing the dwarven gold-lust and given by Sauron in hope of corrupting the wearers, still causing trouble by contributing to Balin's doomed re-occupation of Moria.
Or not?