Adamantite Ore

Adamantite Ore is an ore that is added to a world as a reward for "purifying" it. It is used to craft the Adamantite Forge and Adamantite Bars, therefore, it is the basic ingredient for all Adamantite items. The ore will not appear in the world until the player destroys a Demon Altar with a Pwnhammer. This will "bless" the world with deposits of either Adamantite Ore, Cobalt Ore, or Mythril Ore. These ores will then be found randomly like any other.

It is colored red and can be found near the bottom of the Cavern layer where the lava begins. You need to have at least a Mythril Drill to be able to mine it. To craft all Adamantite equipment, the player needs to gather 144 Adamantite bars, plus thirty ore for an Adamantite Forge, for a total of 750 Adamantite Ore.

Trivia
Adamantite gets its name from "adamant" which has historically been used to describe exceptionally hard materials such as diamond. Adamant and variations have widely been used to describe metals and materials with diamondlike durability in fantasy, science-fiction, and mythology, from as far back as "adamantine" in ancient Greek mythology, to the "adamantium" of Marvel Comics (first appearing in Avengers #66 but made famous by the popular X-Men character Wolverine, whose skeleton was infused with adamantium).