A while back I bought a coin sold to me as a John II Comnenus (1118-43 A.D.) Aspron Trachy, that was made out of Electrum. After spending some time trying to attribute the coin I now believe that it is a gold Hyperpyron instead. This is the only coin I have from this era, so I don't know much about it. The coin is somewhat curved (saucer shaped?) and appears to be in great shape. I believe some of the outer rim area was trimmed off at one time or another based on photos of other such coins I've seen. This one weighs 2.55g and is 23.3mm. With proper magnification you can see the beard of the priest on the reverse (he is one on the left as you view it). I'm not really that into this era's coins like I am ancient Greek and Roman coins, but I got this cheap compared to prices online so I was happy.
