https://rpc.ashmus.ox.ac.uk/countermark/1367 

GIC —

uncertain monogram, ΤΥΡ (or TAR) ?

incuse 

7 mm tall, 7.5 mm wide 

Uncertain (Uncertain)

examples applied to coins of Laodicea Catacecaumene. If ΤΥΡ it could stand for Tyriaeum, a city close to Laodicea Catacecaumene, which never struck coins