Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1683 
GIC
S C
square or rectangular 
c. 5.5 mm 
 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC V.3, — (number not assigned), type ID 84004 Show 2872 5 5.3
RPC V.3, — (number not assigned), type ID 84002 Show 2873 10 5.3