Magnentius, AE3, 24 mm (smaller module type), Rome. AD 351-352. 

DN MAGNEN-TIVS PF AVG, bare-headed, draped, cuirassed bust right, A behind head.
GLORIA ROMANORVM, emperor on horseback galloping right, no 
shield, wielding spear at a bare-headed enemy half-kneeling 
before the horse, broken spear and shield beneath the horse. 
Star in upper right field. 
Mintmark RQ. 

RIC VIII Rome 209. 

With permission of Monnaies d'Antan, Nov 2009.