Larry Kidd, one of the best if not THE best painter we have had here stated several times it was a paint system, but he struggled to replicate it, it had been broke down into golds/coppers/purples the list went on and on.
Cold Casting a bio would add more weight you do not need if using for a suit, HEZ did some cool P1 cold casting, and it added quite some weight, and the look although very cool was not film accurate.