Different Rare Materials

I found an NPC last night that allowed me to create rares. Nothing unusualy you may say, but these rares all had different names than usual.
i.e:
Normally you get: Steel, Paper, Leather Square etc etc.
This one allowed me to create: Dilment (Can't remember spelling) steel, Velium Paper etc etc.
They all had special names.

Can anyone tell me what this special material is for?
Can I use this special Steel to make armour that needs normal steel?
Does it give any special bonus?
Is there rare armour that needs these wierd rares?

I believe that later in the game there is a need for these special named materials when crafting the later armor. They do not substitute for the standard rare material.