They would not have used pure nickel for the pamor, probably some recycled nickel alloy material.
The sarung is behind the blade, it is a similar sort of thing to the one at the top of this page:-
http://www.kerisattosanaji.com/NEKAMUSEUMPAGE3.html
pure art, nothing realistic about it --- but then that's what Mr. Neka is all about
:- art.