Enamelled copper-alloy ring brooch

Roman ring brooch, overall diam. 3.5cm. Consists of a cast recessed ring, with open centre, inlaid with red and pale green (or perhaps originally white) enamel in wedges, but much deteriorated. Around the edge cast in one with ring, are 5 lobes (originally 6 - one knocked off in antiquity and break worn) which have likewise had enamel in them. The colour now is orange, and may be original. One lug more solid and setting smaller - behind it is the double pierced lug attachment for the pin coil. On the opposite lug are the remains of the catchpate. Pin missing.