Countermark

https://rpc.ashmus.ox.ac.uk/countermark/580 
GIC 457 i
star of six rays (on obverse)
circular or oval 
c 4 mm 
there is possibly a crescent below the star on some of the examples? 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 4940 Show 4940 7 1
RPC I, 4940 Show 4940 8 1
RPC I, 4940 Show 4940 9 1
RPC I, 4951 Show 4951 11 1
RPC I, 4942 Show 4942 10 1
RPC I, 4951 Show 4951 12 1
RPC I, 4943 Show 4943 15 1
RPC I, 4951 Show 4951 7 1
RPC I, 4951 Show 4951 14 1
RPC I, 4942 Show 4942 11 1
RPC I, 4942 Show 4942 7 1
RPC I, 4943 Show 4943 8 1
RPC I, 4940 Show 4940 10 1
RPC I, 4951 Show 4951 15 1
RPC I, 4940 Show 4940 11 1
RPC I, 4940 Show 4940 12 1
RPC I, 4940 Show 4940 13 1
RPC I, 4940 Show 4940 14 1
RPC I, 4951 Show 4951 13 1
RPC I, 4943 Show 4943 18 1
RPC I, 4951 Show 4951 16 1
RPC I, 4943 Show 4943 19 1
RPC I, 4952 Show 4952 8 1
RPC I, 4951 Show 4951 17 1
RPC I, 4951 Show 4951 18 1
RPC I, 4940 Show 4940 16 1
RPC I, 4943 Show 4943 17 1
RPC I, 4951 Show 4951 1 1
RPC I, 4940 Show 4940 17 1