Foe StoneLevel 12 Uncommon

This lodestone is set into a chain, and when aimed toward an enemy, it grants you understanding of your foes' weaknesses.

Wondrous Item        13,000 gp

Power ✦ At-Will (Minor Action)

Choose one creature you can see. You learn all the target's vulnerabilities, as well as which of its defenses is lowest.

Published in Adventurer's Vault, page(s) 172.