Adamantite among Orichalcum were ultra rare metals in the New World. Though by YGGDRASIL standards they were a grade below the Prismatic Ores. In addition Adamantite was the highest rank an adventurer could reach.
In the Anime, adamantite is portrayed as a polished dark Blue to black metal.
Adamantite was a rare magical material which was generally known as the hardest metal known in the New World. The metal was highly expensive, even making a small piece like an adamantite plate was astronomical. Adamantite like most metals can be melted with extreme heat.
- So far only six examples of Full Platemail cast out of Adamantite exist in the Overlord series: Guardian Armor, armor worn by the Four Imperial Knights, and Zaryusu Shasha's armor.