Blackrock, the unbreakable, jet black mineral that is found only in the deepest of mines. Numerous experiments have been performed with this newly discovered mineral, including those by Rudyom of Cove, and others.

Blackrock is indestructible by any normal means, though by the use of a relatively minor spell, a small amount of the substance can be made malleable for a short time. Because of another of its peculiar properties, blackrock played an important role in the Avatar's last quest in Britannia. Blackrock seems to slow, and block when used in large quantities, the flow of the Ether around it. (For a more detailed look at how the Ether works see: The Ether) This was useful in blocking the harmful ether waves created by the Tetrahedron Generator, so that the Avatar was able to converse more easily with the mage Penumbra. Horance the Liche also used blackrock in the construction of his dark tower, making him immune to the detrimental effects of the Tetrahedron Generator that incapacitated so many mages of the time.

Blackrock also has other, not yet fully explored characteristics, one of which deals with teleportation, as seen with the Black Gate, and the smaller blackrock gem within the castle sewers during the Guardians first invasion. When imbued with powerful magics of some kind, blackrock seems to aid the process of inter-dimensional travel. This magic is beyond even the powers of even our most powerful mages, though perhaps someday its secrets will be discovered.

Blackrock, while widely known in intellectual circles, is far from common, and is in fact the rarest known mineral, surpassing even gold. Known deposits have been located in both the Minoc and Vesper mines, first mined by the Fellowship for use in creating the Black Gate. This mineral is not limited to our own world, either. According to the Avatar's companions in the Serpent isle, the Ophidians used blackrock in the construction of their holy objects. Also, found among the Avatar's journal entries from the time of the Guardian's first invasion, blackrock was used in many of the planes that he traveled to.