This is a well known type of ring of which many similar examples have been found. This particular ring is very fine.
The colourful and decorative bezel is engraved with an ant. Other similar rings bear a bee or a butterfly.
The ant is traditionally associated with the Roman goddess Ceres. She is a mother goddess of grain and fertility, and from her name derives the word 'cereals', her gift to humankind. This ring was probably inteded to bring prosperity to its wearer.