I have a 24" Zildjian ride cymbal that I got with my first drum set. The stamp says Avedis Zildjian Co Genuine Turkish Cymbals Made in U.S.A.
I'm not sure how old it is. I bought the drums second hand somewhere around 1986, and the set was is bad shape then. I would guess it was made in the 70s sometime.
So I'm going to try to clean this thing up, or at least do some research to see if the tarnish adds to the sound.