Vessel made up of three pieces of agate and six enamelled gold mounts. The boat-shaped bowl is decorated externally with a carved band of interlaced ovals separated by five-pointed fleurons. Running around the lip is a smooth gold mount, enamelled on the interior, with overlaid adornments of green leaves and white berries with incrustations of rubies and emeralds. At the stern is a Cupid enamelled in white with his bow and quill set with diamonds. He is riding a monster with the head and body of a dragon and a coiled tail, enamelled in opaque violet, blue, ochre and white, and translucent green, blue and tan. A floral garland enamelled in opaque tones covers the outer body and interior of the vessel, perhaps to hide a crack, with a mask in the centre of the inner face.

The piece was attributed by Alcouffe to Pierre Delabarre, "the master of the dragons", and forms part of a group of works with similar mounts, such as the so-called Amor ewer and Minerva ewer, both at the Louvre, OA 10409 and MR 445. The Minerva ewer is signed on the base by Pierre Delabarre, which has led to the attribution to him of both pieces as well as two others also in the Louvre, a wall sconce, MR 251, and the so-called mirror of Maria de’Medici, MR 252, both acquired in 1684 by King Louis XIV.

On the dragon’s breast, there used to be a sapphire which was described in the 1776 inventory as "octagonal, elongated, rose cut, set with twelve beads", and which was declared missing in the report issued by the Spanish Embassy in Paris when the Dauphin’s Treasure was returned to the Spanish government, although its position on the piece is incorrectly given there as the animal’s head. It was replaced at an unknown date with a piece of red glass, perhaps during the 19th century restoration carried out by Pedro Zaldós.

The bowl of the vessel may be an ancient piece recarved in a French workshop, as there are four similar pieces, one in the Museo del Prado and three in other collections with older mounts. Among them is a gift from Charles IX of France to Archduke Ferdinand II in 1570 which displays the same motifs as the Madrid vessel.

The state of the work in the 19th century can be seen through the photography of Juan Laurent y Minier, "Vase agate sardoine, montures d’or avec émaux et pierreries, XVIe siècle, règne de Henri II", c. 1879, Museo del Prado, HF0835/16.