Its shell was made of an opaque white enamel and it contained a gold yolk.
Barovier went on to develop lattimo, or milk glass, which imitated the pure opaque whiteness of porcelain, and calcedonio, which reproduced the effects of chalcedony, agate and malachite.
The Hen Egg, as it became known was crafted from gold, its opaque white enameled 'shell' opening to reveal its first surprise, a matte yellow gold yolk.