What is "Black Armour Piece" used for?

I searched for the item ID and the item name in all of the quest data and found nada. I think it's a useless, rare etc item that was going to be used for a quest but ended up not happening.

Thank you for your kind help.

Thanks all for your generous advise. ^_^

Deeply Appreciated it~ ^_^

I suddenly have a wacky idea... i shall try to collect 100 of it to see if i can make a monster crystal out of it... LOL... god knows what i'm going to get