The Oracle (3.5e Equipment)
From D&D Wiki
The Oracle: The Orcale is a fist sized and perfectly smooth gem that emits a gentle blue aura.
The Oracle was a gem in the court room of Heironeous. It could distinguish lies from truth in even the most powerful of demons. Unfortunately, in a war with his brother Hextor, the gem was destroyed and scattered throughout the mortal realm. The shards of the gem still contain some of its power,but the power they contain is nothing compared to the gem in its fullness.
The Oracle is considered a shield and is wielded in ones off-hand. When equiped, the gem grants a +2 insight bonus to AC as well as True Seeing and a 40 foot aura of Zone of Truth (cast at a CL of 20).
Strong Divination; CL 20; Weight: 1 lb.