This coin is completely silvered and has what appears to be a stylized star (or maybe an equilateral cross) in the center strip of the helmet. Normally this strip is engraved showing just a few rivets and sometimes a bit of design like a few lines; something this elaborate is unusual.
Constantine I
A.D. 319
19mm 2.5gm
CONSTANTI-NVS AVG, high crested helmet, cuir., spear across r. shoulder, shield on left arm
VICT dot LAETAE PRINC PERP, [ Joyous (well-earned) victory to the eternal Prince] two Victories stg., facing one another, together holding shield inscribed VOT PR [VOTA POPULI ROMANI (vows of the Roman people)] on altar inscribed with the letter I.
In exergue dot BSIS dot
RIC VII Siscia 84