I plucked this from a shop's unsorted material today. Everything else was fairly junky modern stuff, so initially I was a bit concerned about the possibility of this being a modern reproduction, but in examining it closely, I'm now reasonably convinced of its authenticity. However, while I feel like it ought to be easy to attribute, the reverse legend, which I take to begin with "Γ", is not proving useful to me in that task.
It's about 18.5 mm across, with the weight coming in at just over 7 grams.
That's an awfully nice coin for a pick box. Congratulations!
All I can add is to be cautious when using numbers from specialized references like Calciati if you don't have the book in front of you. There may be minor variants that each have their own number. "Sear GCV 1223 variant" or "Sear GCV 1223 type" would be a safe general attribution, even Sear 1223 is probably enough. Sear is more of a broad type catalog with some implicit latitude. As an example of what I mean by variants, the coin plated by Sear has IEΡ-ΩNOΣ below the trident rather than IEΡΩ-NOΣ.
Excellent looking coin!....I really do like this type.. Here's the one I chose for my 12 Olympian set with the different legend break....Also there are a lot of different control marks, bottom left and right to take into consideration...