The glove is either metal, or leather. No plastic or cheap materials here.
The metal is also painted to give it a weathered, aged, tarnished appearance. The sculpted texture on the strips on the back of the hand (I’m assuming he cut these out of something particular in the movie?) are darker than the rest, making the carved marks stand out.
There’s also some dirt added to the glove, but it’s not over the top or excessive. Or maybe it’s blood – you decide.