Countermark

https://rpc.ashmus.ox.ac.uk/countermark/580 
GIC 457 i
star of six rays
circular or oval 
there is possibly a crescent below the star? 

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