Obsidian is a Tier 2 (Common) type Metal Crafting Materials in Dragon Age: Inquisition (DAI). Materials such as these are found in the field by harvesting, defeating enemies, completing quests or obtained as a reward for War Table Missions.
Medium armor rating / damage (staff damage type: cold)
1.5% chance to stagger target on hit
1.5% chance to stagger attacker on being hit