Shadow Iron is harvested using a pickaxe or shovel. There is a 1.5% chance to find this colored ore while mining. You'll need to level 70 in mining to start smelting this ore. Having a weapon crafted with Shadow Iron ingots will give you 20% cold dmg and 50 durability. And a total of 12% Resist.
Physical resist: 3
Fire resist: 2
Cold resist: 0
Poison resist: 0
Energy resist: 7