Could be uranium metal? Or titanium parts.
Even so, Somebody could sculpt the same shape using less pricy materials or even do a model kit.
I am comparing this to robots at premium prices, this includes things like the new "Giant Gorg" by sentinial, Shin Getter by fewture, perfect change shin getters etc..... They are way complex in design.
Don't get me wrong, is nice, but you could get so much more for what you going to pay. I would think Bandai could do a better and cheaper option if they had the rights and license.