Copper Ore is an item in Postknight that is used to upgrade items with the Blacksmith or exchanged with the Trader.
Due to its highly prolific nature across all the enemies in the first two areas, the best routes for collection are the ones that provide the most enemies to defeat. That way, the chance to collect Copper Ore is increased significantly as the enemy density increases.
Copper Ore is used with every set of equipment in Tier One and Tier Two, eventually being replaced by Silver Ore when using the Blacksmith to upgrade Tier Three and Tier Four equipment.
In trading, Copper Ore is used similarly to other common items. It is unique however, always required to trade for a Copper Bar similarly to Silver Ore to the Silver Bar.