Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1379 
GIC
laureate head r.
rectangular (or square?) 
5–5.5 mm 
on reverse; no certainty cmk applied at Pella 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC II, 2098 Show 2098 4 2