I have this belt for several years now and the belt buckle is naturally subject to wear and tear.

On the most exposed spots the outer layer is now completely worn of and I wonder

  1. Is this an example of passivation of the inner material?

  2. What is the outer layer made of? Stainless steel?

  3. What is the metal under the outer layer? It looks (and smells) like copper but why would they make it out of copper? Copper is – as far as I know – more expensive (by volume comparison, because the belt buckle can't be made smaller) than stainless steel?

  4. Wouldn't it be cheaper to make it only from stainless steel (assuming the outer layer is from stainless steel)? It would also be better from health perspective because I suspect the inner layer causes skin irritation.

I intentionally scrubbed the bottom edge of the buckle before taking the photo to reveal the real color of the metal, on the top edge it is presumably covered by its natural oxide layer (copper has it green, right? But it's just a thin layer so it can look different I suppose).

I am kind of ashamed answers to these questions aren't already known to me because this effect happens on a lot of daily used metal objects...

belt buckle

  • 1
    $\begingroup$ I believe it may be bronze. That was a bit cheaper considering the fact that the Bronze Age came before the Iron Age. $\endgroup$ Jun 17, 2017 at 12:53
  • $\begingroup$ Looks like nickel or chrome plated copper, maybe. If it's old enough, it may come from an era when 18-8 stainless was a lot more expensive than it is now. Almost certainly it would make more sense to make a modern buckle out of 18-8 SS. $\endgroup$
    – hBy2Py
    Jun 17, 2017 at 13:26

1 Answer 1


1 =no , 2= no, 3 Likely brass , 4= no. The buckle is likely a brass although the bottom edge where you polished it is copper color . That could result if you used some cleaning agent. It could be made from copper but modern mass production would use brass. It was plated with nickle and / or chromium. Nickel plating is usually put down first , under chromium plating.

  • $\begingroup$ Thank you for the answer! I haven't used any cleaning agent, just a metal scourer. $\endgroup$
    – VaNa
    Jun 18, 2017 at 14:39

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