Why do I always look at the plates of every book on antiquities I come across? Because you never know what you might spot!
So I got to play around with Neapolitan weight conversions to figure out what Riccio thought this little coin weighed. The various reportings of the Naples libbra in the 19th century all are between 320-321gs. So that puts the trapeso (1/360th of an libbra) at c. 0.89 g. and this specimen as having a reported weight of c. 3.55g.
Rough translation of Riccio’s commentary: “It has not been possible to assign a mint to coin with a different style of engraving. In terms of weight, it almost corresponds to the half-ounce of this series, although it lacks the mint mark of Luceria. Could the ball, about half the size of that typically found on this series, be the symbol of semuncia? We have had two beautiful ones from the surroundings of Luceria. Others better informed will pass judgement on this conjecture, since it has hitherto been impossible to situate the fractional denominations of the as corresponding to this type, sometimes attributed to Campania, and sometimes to Apulia.” (corrections welcome as always)