This silver coin is a Hexagram struck during the reign of Heraclius & H. Constantine co-emperors (613- 641 AD). Approximate specs, (22mm 6.8g). Due to the heavy use of gold and bronze coinage in the empire, Byzantine silver coinage is more scarce!
Obverse: The two emperors seated, facing.
Reverse: The cross potent on steps.
This coin has been graded Fine by NGC.