Here are a couple metal detector finds from the UK that are in bad shape. Both are DIOCLETIAN and these are actually a green color but where photographed under a lamp that makes them look yellow(I wish they where gold).
This one looks like it either has a countermark on the neck or thats just damage to the patina.
DIOCLETIAN Æ Follis. Rev. GENIO POPVLI ROMANI, GENIO standing left.
4.4ggrams25mm

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This one is also a UK metal detector find. DIOCLETIAN FOLLIS 5.6ggrams26mm I would say the reverse is GENIO holding patera over alter with cornucopia and A?(it looks like an A or star or something)in right field.-The closest I found is this-Aquileia
RIC 27a Diocletian AE Follis. IMP DIOCLETIANVS P F AVG, laureate head right / GENIO POPVLIROMANI, Genio standing left, naked except for modius on head & chlamys over left shoulder, holding patera over tripod altar & cornucopiae,
