Gold and iron play no more than a metaphorical role in this early Vance story. The original title, Slaves of the Klau, while considerably less poetic, is more accurate. The story concerns an Earthman and a woman from another, more advanced race, who are taken captive by the Klau.
This is a very John Campbell-esque story, in that it's apparent early on that only Earthmen, despite their low level of civilization, have the strength and dynamism to keep going in the face of adversity. There's little of the usual Vance wordplay and aloof would-be sophisticates come in only via the aliens. Instead, it's a straightforward adventure story. That said, it's still well-written, and worth reading.
Not a good introduction to Vance, but if you're looking for good old fashioned space opera, when men were men (and women were unfortunately mostly decorative), this fits the bill.