I've tried to create an evidence based site to document what we know (or think we know) about different die stamps.
That's an early 1970s stamp by appearance, although we don't really know exactly what year the 60s stamp finished and this particular 70s stamp began. We do know that it didn't happen at the stroke of midnight on December 31st, 1969.
This section deals with the 3 attributes I'm using to identify it, mainly in the context of how to tell a late 50s small stamp from this 70s stamp (because there is a persistent internet myth that it is "hard"):
http://black.net.nz/avedis/avedis-gallery.html#70s
Edit: I should mention that the side on shot of your stamp makes it a bit harder to judge the vertical alignment of the H of turkisH over the E of madE, but you should have no trouble when you look straight on. I've been tricked a few times before by side on shots and I think I've learned to compensate properly. But please let me know if the E isn't to the right of the H. I do also need new reading glasses. People who know me will know I'm a bit slow about making an appointment to get another eye exam and a new pair. ;)