I lived in Puerto Rico as a kid and thought Arecibo was cool as hell - the dish was suspended over a valley and larger than you might think (of course Goldeneye is a great reference). It’s a major loss to a bunch of scientific efforts and to my understanding the China dish, while massive, does not have the same capabilities that have been lost.
There are mumblings of rebuilding, but given that maintenance funds were insufficient I wonder how much more construction would be for a new one.
As to the material, to my recollection it was a bunch of metal mesh panels, I would guess aluminum(?). Always wanted to try riding / sliding on it.