A sovereign ring is a ring which typically has a gold sovereign as a primary decorative feature, with the obverse face as the visible detail. The coin may be either genuine or replica tender, and may be either a sovereign or half sovereign. In the United Kingdom it is also common to use custom coinage bearing such motifs as the 'Three Lions', or other similar imagery as Saint George, or a Welsh Dragon.
English rapper Louise Amanda Harman is known for wearing a sovereign ring, hence her stage name of "Lady Sovereign."
References
Sovereign ring Wikipedia(Text) CC BY-SA