Copper used with brass on lenses?

Here's an odd question. I bought a number of lenses as a lot and there was included a tiny longish lens that was un recognizable as a lens because it was obscured with dirt. So I cleaned it. It is mainly brass, with a functioning aperture so it's a camera lens I guess, but it also has what appears to be a copper part to the barrel. Was copper used with brass for lenses? It looks oldish and very small. Certainly not a large format lens but I was curious if anyone has seen a mix of metals on lenses

Don't have it with me so no picture to show but could post one later if anyone is interested

As you probably know brass is an alloy of copper and zinc, it is harder than copper. The "lens" may have been made by an amateur, and the choice to use copper may be simply that was what was to hand.

Lancaster of Birmingham made a series of lenses called the Rectigraph (RR type)? This was made in differed coloured brass - probably acheived by just varying the proportion of copper to zink. They look very striking - when cleaned!

How did you determine that part was copper?

I'm a machinist, with a lot experience working with "yellow" metals.
I would not be confident in making that distinction entirely by eye.

- Leigh

True, I'm not experienced with metals. I noticed this part of the lens looked like copper...rather like a new penny once cleaned up. Of course it might be a different colored brass but I have never seen anything like it before.
I also didn't know that brass could be so much different in look. I know it can be more "deep yellow" and light yellow, but I didn't know it could have such a coppery hue. I also wonder why it would be a different color. I can't see that it would change it's purpose of the part which looks like some connecting ring. It has a thread on the inside.
It's quite attractive in any case.

I'm not saying it's not copper, only pointing out that other options exist.

There are many "red" alloys. And they will look different under different illumination.
Most will look "redder" under an incandescent light than under direct sunlight.

- Leigh

I understand you were just letting me know there were other possibilities. It was interesting to me to see this color combination on one lens. I've seen aluminum ( speaking looSely. Again, I know nothing about metal alloys, just that it is silver color and I assume it is aluminum)and brass but nothing like this.