Cameos are carved from various materials such as shell including abalone, wood, bone, coral, ivory, agate and naturally layered hard stone and come in a variety of colors.

Molded cameos are usually glass and can be one or two colors, are swirled colors. Usually glass cameos are very shiny. Cameos are also molded from plastics, such as the Wedgwood Style, Imitation Shell, or two-color celluloid. Plastic can make a great imitation of shell. Occasionally, but not very often, natural materials are molded. An indication of molded cameo is a roundness of detail and a lack of sharp and precise lines. An indication of glass is the presence of mold marks and ridges or dimples on the back.

Shell cameos are carved from a single piece of shell. Shell is soft and very easy to carve and the cameos are usually two colors. Shell will have a concave back and is usually quite thin with the exception of abalone and mother of pearl which are usually flat on the back. Coral Cameos are usually a single color with a flat back.

Agate cameos are carved pretty much the same way that shell is carved, with one advantage the carver is able to see the layers of color from the side and knows that these layers will basically be flat. Stone is much harder to carve. A good hard stone cameo may be under carved quite a bit at the junction where the portrait meets the flat plaque, at first giving the impression that it is an applied cameo.

Amber Cameos are rather new to the market place. Carved from natural amber with the reverse intaglios being hand carved.

General rule to distinguish between molded and carved cameos is this: Generally a natural material would be carved, while glass and plastic would likely be molded but could be carved though not very likely. Molded cameos can be two colors by the simple device of pouring one color into the mold in a thin layer and then following with a thicker layer of another color.

If you are buying for value distinguishing the type of cameo could be very important. If you are buying because you “love” the piece, then that's all that matters.