3rd-6th century A.D. A polished amethyst cabochon bearing intaglio crowned profile bust, circular boss to base of hoop set with a turquoise cabochon; set into a later substantial silver seal ring with D-section hoop, expanding at the shoulders to a quatrefoil bezel, central architectural circular cell on four legs styled as serpents' heads, their bodies and tails tracing the outline of two of the bezel 'petals'. 47.11 grams, 46.71 mm overall, 18.99 mm internal diameter ( approximate size British Q, USA 8, Europe 17.49, Japan 16) (1 3/4 in.). Acquired on the UK art market, 1971-1974. From an important London collection.