>>5629828The first word that comes to mind is "greebling", but just "decorating" is probably better.
If you want to really get into it, name the method that would have been used to decorate the armour if it were a real object. Engraving, etching, inlaying, damascening, whatever. Your pic related doesn't really look like the result of a realistic manufacturing process, so for this case that's probably out.
