Steelhide

Steelhide is an Earth subspecies, created by user OmegaGrox 

Lore
To help survive in Dragonhome, some more subterranean dragons grow scales coated in a shiny, steel-like coating. This coating may build up in certain places if the dragon is injured, forming rock-like clusters that stick out of them. These scales are excellent for defense, and even camouflage in mines and caves.