earthen keystone

This strange hexagonal relic is made of grayish stone, carved with intricate designs or diagrams and set with small gems.
The one the party found originally had been broken near one of the six points; the gray stone shards the party reclaimed seemed to be part of it. Before it was cleansed (Session 31) it also had a powerful Enchantment aura in addition to the Conjuration aura still present on it. In Session 32 it was repaired and shows no sign of missing parts.
To Detect Magic, it shows Conjuration.

Identified

This relic was originally designed to strengthen the power of earth elementals in its area of influence. Its influence reaches out several miles but is very subtle outside of its immediate vicinity. It was placed here a long time ago to keep the river from cutting the land in this place, as one of a series; its larger purpose is unclear.

Prior to the cleansing

Ogremoch was influencing this relic, as well as a powerful devil (of unknown kind or name). While the elemental power remains, the touch of the devil and Ogremoch's power are now gone - removing the fiend from the slab seems to have wrested it from the elemental's control.

Item type

Religious / Ritualistic

Weight

~4500 lbs

Dimensions

A hexagon 4 ft across by 6 inches thick