Brass Wire/cable??

While walking down a creek I came upon an old short, stubby wooden electrical pole. I suspect that in last years flood it washed down(approx. 350Yds.) from the old railroad.
I know I'll probably get some flak on here for it, but it had a '10 piece of non-ferrous attached to it and I took it! The way i see it, it's in the middle of a public trout stream with a public access and about 200Yds. from being in the river.
My question is, the wire/cable seems to be brass. Could it just be a lighter colored copper or an alloyed copper or might it be brass? It is comprised of 7 strands of wire and each are a little bit bigger than a pencil lead. It seems to have been the pole's support cable.
Thanks for any input.

Just did that. There's a clear difference. Filed a piece of yellow brass, exact match. I just don't get why they would use brass cable for a support line!

It is possible that what you have found is Beryllium copper, if it is please avoid filing it in and breathing in any of the powder. Is the wire much stronger than normal copper?