Countermark

https://rpc.ashmus.ox.ac.uk/countermark/928 
GIC 813
denominational mark Ϛ
circular 
6.5 mm 
Sometimes on reverse 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC X, — (number not assigned), type ID 61345 Show 1689 6 10
RPC X, — (number not assigned), type ID 61345 Show 1689 5 10
RPC X, — (number not assigned), type ID 61345 Show 1689 1 10
RPC X, — (number not assigned), type ID 61345 Show 1689 2 10
RPC X, — (number not assigned), type ID 61346 Show 1688 1 10
RPC X, — (number not assigned), type ID 61347 Show 1719 4 10
RPC X, — (number not assigned), type ID 61348 Show 1720 6 10
RPC X, — (number not assigned), type ID 61348 Show 1720 4 10
RPC X, — (number not assigned), type ID 61348 Show 1720 3 10
RPC X, — (number not assigned), type ID 61350 Show 1717 1 10
RPC X, — (number not assigned), type ID 61352 Show 1718 11 10
RPC X, — (number not assigned), type ID 61352 Show 1718 3 10
RPC X, — (number not assigned), type ID 61357 Show 1724 5 10
RPC X, — (number not assigned), type ID 61357 Show 1724 9 10
RPC X, — (number not assigned), type ID 61357 Show 1724 10 10
RPC X, — (number not assigned), type ID 82877 Show 1726 2 10
RPC X, — (number not assigned), type ID 61358 Show 1732 3 10
RPC X, — (number not assigned), type ID 61358 Show 1732 4 10
RPC X, — (number not assigned), type ID 61358 Show 1732 2 10
RPC X, — (number not assigned), type ID 61358 Show 1732 7 10
RPC X, — (number not assigned), type ID 61358 Show 1732 13 10
RPC X, — (number not assigned), type ID 61362 Show 1730 5 10
RPC X, — (number not assigned), type ID 61363 Show 1733 1 10
RPC X, — (number not assigned), type ID 61363 Show 1733 4 10
RPC X, — (number not assigned), type ID 61519 Show 1629 12 10
RPC X, — (number not assigned), type ID 61345 Show 1689 10 10
RPC X, — (number not assigned), type ID 61345 Show 1689 14 10
RPC VI, 5352 (temporary) Show 4985 2 6
RPC X, — (number not assigned), type ID 61353 Show 1729 2 10