About the only reason to kill these is that they'll come along with the collared gemgetters (levels are off, gemgetters are generally higher than silviers).
Drop flawed weapons/shield and worn armour. Gemgetters drop the balanced and 89% armours.
I got some leather armor and some scale armor off these, they also drop some nice gems on occasion.
there are lots of other mobs in the dungeon, and they go as high as orange to a level 50 as you go down deeper into the dungeon, perhaps even higher level than that. but that is as deep as I was able to get.