Engraved on this small ovoid ringstone is a profile bust of Eros, identifiable by his wings. His long wavy hair is bound in a fillet, with the ties falling onto his shoulders. In the field before him is a syrinx (Pan pipes).
Sapphires are fairly rare in Roman jewelry. Pale stones like the example presented here are thought to have originated in Sri Lanka, called Taprobanê by the Greeks and Romans (see p. 718 in M.S. Krzemnicki, et al., "Gemmological Analysis of a Roman Sappire Intaglio and Its Possible Origin," The Journal of Gemmology 36, no. 8).