Onyx

Onyx, a rare Semi Gemstone. Even though it is not containing pure energy it is considered a gem due to its durability, like glass sand it can be melted with a bit higher temperature, but the outcoming product is as hard as steel.

Uses
Onyxis used as a material to produce hardened glass often known as the Onyxium Glass, it is used in showcases, containers, and after the year 921 it has proved to be the best way that a fighter can protect his eyes during combat, mostly against the Wiverns. It started figuring as eye protection due to the fact that the Green Wiverns can spit acid.