Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1738 
GIC
star of eight points with central pellet
circular 
4 - 4.5 mm 
on obverse 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 3367C Show 3367 2 1
RPC I, 3367C Show 3367 3 1
RPC I, 3397 Show 3397 6 1