Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1294 
GIC
COI
rectangular 
7 x 4 mm 
probably a version of COL (Col)onia 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC V.3, — (number not assigned), type ID 70082 Show 4230 16 5.3
RPC V.3, — (number not assigned), type ID 70088 Show 4228 5 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 3 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 7 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 8 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 10 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 12 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 14 5.3
RPC V.3, — (number not assigned), type ID 70088 Show 4228 9 5.3
RPC V.3, — (number not assigned), type ID 70088 Show 4228 67 5.3
RPC V.3, — (number not assigned), type ID 70088 Show 4228 55 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 6 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 13 5.3
RPC V.3, — (number not assigned), type ID 70135 Show 4238 5 5.3