To produce a hand-carved shell cameo, most artists follow the following steps:

• After the sardonyx or carnelian shell is selected, it is divided into two parts. One part of the shell is used for souvenir items and trinkets, and the other part — thicker and more richly colored — is used for cameos.
  
  
• The part of the shell to be used for cameos, called the cup, is then divided further by a cutter. The back of these pieces of shell are then smoothed and rounded, and finally attached to a wooden stick for easy handling by the carver. The rough, curved outer layer is left exposed for carving.
  
  
• Carvers work with a carving tool called a bullino, introduced by Italian carvers several hundred years ago, or small dental drills, to grind away shell.
  
  
• After drawing a sketch of the subject matter on the shell, the carvers use traditional cameo carving tools to create the image. Most carvers sit near windows to take advantage of natural light, doing the majority of the work by hand. Cameos can take a few hours or a few days to complete.

Thanks to Anna M. Miller's book Cameos Old & New for production information.