I actually just sold one for 15 bucks in worse condition. Mine was from Cyzicus. They are very popular. Rarity I couldn't tell you though
indeed, nice legend and mint mark, still and attractive coin i think. i purchased this one paid just under 30 with shipping...not a bargain but i'd say reasonable. i like yours better.
Julian II, Heraclea, AE 1. D N FL CL IVLIANVS P F AVG, Pearl-diademed, draped and cuirassed bust right / SECVRITAS REIPVB, Bull standing right, above two stars. dot HERACL dot A. RIC VIII Heraclea 103. RIC lists it as scarce.