Roman Amethyst Intaglio of a Girl Riding a Sea Monster, 1st Century BC/AD

This was possibly made by the master carver Dioscurides, who was the favorite gem carver of the Emperor Augustus.

It is possible that this intaglio portrays one of two possible subjects, the nymph Aura or a Nereid riding on a sea-bull, sea-goat or some other type of horned sea monster. A small seal swims in the ocean behind them.