I cleaned this up the best I could. I'd never seen a mint mark like it before. I "believe" it to be a Roman mint mark, possibly the 4th officina. I believe it to be: Gratian AE3. D N GRATIA-NVS P F AVG, pearl-diademed, draped and cuirassed bust right SECVRITAS-REIPVBLICAE, Victory walking left holding wreath and palm branch Mintmark RQVARTA What say you?