Giovanni Ambrogio Miseroni, a talented hardstone carver from the Italian Renaissance to whom this cameo is attributed, worked with agate from the Grisons featuring a wave-like, cloudy structure, without the clearly contrasting layers traditionally used in glyptic art. The stone has tawny hues disposed in irregular forms with a milky, almost mauve interior. The diffuse veins of the agate appear to solidify in the opalescent body of the goddess. While the sculptor skilfully used the yellow layer to represent the blonde hair of Venus, his work reminds us that shapes can already be seen in the bands of agate, even before a gem cutter sets to work.
At the heart of the cameo, Venus and Cupid are shown sleeping next to one another. Nude on drapery, Venus embraces her son within the large agate shell that shelters them. This form is not insignificant: it recalls the origin of the goddess, who rose from the froth of the sea. The scene does not portray the birth of Venus from the ocean, however, since she is already depicted here with her son, Cupid.
The cameo is encircled by a silver-gilt mount. Hugging the shape of the agate shell, it is topped by a swan, which could be associated with the metamorphosis of Jupiter to seduce Leda. In reality, it plays on the theme of the spied-upon bather, as well as the transformation of gods into animals and stone into flesh. The inventory of the Mazarin collection, which contained the cameo and its cup, already mentioned the ‘silver-gilt rim’ that adorns the lid.
Historically, the cameo was designed as the lid of an agate cup in the shape of an oval shell. Its chiselled and gilded silver foot represents a dolphin, set upon a shell. When it reappeared at a public auction in Paris in 1968, the number 376 engraved on the foot identified the cup as part of the royal collection of hardstone vessels, which led the Louvre to pre-empt it. The large shell formed by the cameo is like a trompe-l’oeil of the actual shell formed by the cup: in such a way, Venus and Cupid appear to float within on invisible waves.