That appears to be a 1960s stamp. I'm not the expert (Bill Hartrick aka Drumaholic is) but I've recently taken the position we need better documented info so we don't get asked the same question over and over again. These are the attributes I am looking at:
Presence of "the three dots".
The stamp is well formed and clear.
The font for the Ottoman (squiggly) part of the stamp and the ZILDJIAN Co. is in bold relative to the other English text.
The vertical alignment of the H of TURKISH over the E of Made. The 70s stamp shows both lack of that alignment and lack of the bold for ZILDJIAN Co. and the Ottoman portion of the stamp. The 70s stamp also lacks the 3 dots, which is what seems to confuse people between late 50s and 70s.
So an annotated pictorial:
late 50s (aka "small stamp")
[img]http://black.net.nz/cym2014/50s.jpg[/img]
which has the alignment, the bold, but no 3 dots. Note that it says "font weight" in that annotation but I found that confused people so I'm now calling it just bold.
60s (actually early 60s because there is also a late 60s)
[img]http://black.net.nz/cym2014/60s.jpg[/img]
which has the alignment and the bold, doesn't have the three dots
70s (although in the late 70s there are others)
[img]http://black.net.nz/cym2014/70s.jpg[/img]
with lack of alignment and lack of bold and lack of 3 dots and often not pressed in as well as the 50s.
This is a little toolkit for recognizing these three decades from pictures only. There are other differences in hammering, lathing, bell shape, and heights of the stamps. But you needs hands on to make those observations.
And there are lots of other stamps. Here's the man himself:
[ame]http://black.net.nz/cym2013/ZDatingZildjianCymbals.pdf[/ame]
