Star-steel

Star-steel is a rare, precious alloy made by the dwarves from meteoric iron. Properly forged and worked, it can be much stronger and more durable than normal steel, which makes it particularly desirable for weapons and armor. 
Meteoric iron may very rarely be found above ground, in the crater where a falling star has recently struck the earth, but it is mostly mined from deep lodes known only to the dwarves, where the hearts of fallen stars were buried beneath rising mountains long ago when the world was still newborn and Kordan shaped its stony flesh like clay.