Earth elemental
Earth elementals are beings from the Elemental Plane of Earth. They are roughly humanoid in appearance, and can vary greatly in size and power.
Having both practical and symbolic significance, the svirfneblin of Blingdenstone once relied on earth elementals for many things, but a madness afflicting the elementals caused the deep gnomes to avoid them.
The adventurers defeated mad earth elementals in Rockblight and at the Steadfast Stone. In death, each elemental left behind a large yellow gem which had been it's heart. These gems were given to Nomi Pathshutter who observed that the cracks and cloudiness in the gems showed that these had been afflicted.
The adventures agreed to help address this affliction, and found, and restored Entemoch's Boon and summoned Rocky while there.