The weight is 6.98 gram. I cannot tell you the diameter since the coin is in my bank deposit box. It is definitely larger than a antoninianus but smaller than a for instance a Severus Alexander dupondius.
A silvered dupondius ? Looking like an antoninianus ?? Even though the weight is very high for an antoninianus, I would be curious to reading more about that...(never heard of them) Nice Gallienus coins everyone, here are mine : Gallienus, Antoninianus Rome mint IMP GALLIENVS AVG, radiate head right APOLLINI CONS AVG, Griffin left. II at exergue 3.18 gr Ref : Cohen # 77, RCV # 10180v, Göbl # 718z Gallienus, Antoninianus Cologne mint, AD 257-258 GALLIENVS PF AVG, Radiate and cuirassed bust of Gallienus, seen from front VIRTVS AVGG, Virtus, standing right, holding spear and standard 3,93 gr Ref : RCV #10413, Cohen #1309, Göbl # 8821 Gallienus, Antoninianus Antioch mint, AD 265 GALLIENVS AVG, radiate and cuirassed bust right seen from front VENRI (sic) VICTRICI, Venus standing left, holding helmet shield and spear 3,30 gr Ref : RCV #10370 var, Cohen #1021 var, Göbl #1653g Gallienus, Sestertius Rome mint, AD 253-255 IMP C P LIC GALLIENVS AVG, Laureate and draped and cuirassed bust of Gallienus right CONCORDIA EXERCIT, Concordia standing left, holding double cornucopia and patera. 18.5 gr Ref : RIC # 209, Göbl # 15dd, Cohen #132, RCV #10467 Q
Here is my heavy Gallienus. Gallienus (253 - 268 A.D.) AR Antoninianus O: IMP C P LIC GALLIENVS AVG, Radiate and cuirassed bust right. R: IOVI CONSERVA, Jupiter standing left, head turned right, holding scepter in right and thunderbolt in left. 5.1g 24mm RIC 143F (Rome) Sear 10237
A fellow collector told me that a dupondius of the same die is depicted in Göbl (No. 438k, plate 39). I will try to shot a photo showing the coin besides an antoninianus and a Severian dupondius.