The problem is that the coin was retired, and I can no longer have access to it. In my memory, the size was huge, larger than a tetradrachm, so about 33 cm and the weight was impressive too, perhaps around 28gr. On the other side, there was a square divided in four, with in each sqare : grapes, an axe, and two other symbols. At the time I looked if I could find something similar in genuine greek coins, but I couldn't find anything, so I was very perplexed. I wonder whether it is not supposed to be a specimen of the famous Gelon Tyran tetradrachm of syracuse... but this is only an hypothesis