Cobalt Ore

Cobalt Ore is an ore that appears in the world when the player destroys a Demon Altar with a Pwnhammer. This will "bless" the world with deposits of either Cobalt Ore, Mythril Ore, or Adamantite Ore. These ore can then be found randomly throughout the Underground and Cavern layers. Cobalt Ore can only be mined with Molten Pickaxes or greater quality excavating items. It is immune to all types of explosions. It is the most abundant of the three hardmode ores.

Trivia

 * Cobalt is a poisonous, magnetic metal.
 * Cobalt is named after the Kobold, at that time thought of as a mischievous spirit.