The objects your men are to retrieve are shards of a Welkynd Stone. Look for small blue stones, no bigger than a fist, and illuminated from the inside. The Goblins have been using these as centerpieces for their ritual totems. You'll know these totems when you see them: the Welkynd Stone seems to imbue the totems with a red light.
Still, retrieving the shards should be a simple matter. We're dealing with Goblins, not Dwemer. I'm sure the totems are held together with twine and spit. Just rip the shard out. Even your grunts should be able to handle that.