It looks like
Grierson 394,
Constantine IV 668-85AD,
Decanummium Class 1,
Constantinople. Obv Emperor facing with Gl. Cr. in right (
Shield L?), Rx large I above empty
exergue,
cross to left R to right...Grierson says these may be the result of an inflationary reevaluation of the
money due to
Constantinople being under constant siege by the Arabs at the time, with these taking the literal value of the half folles...as many as seven variant forms of the decanummia during this time period have been noted, mostly delineated by the emperors
bust, whether facing, or 3/4...hope this helps...b