Cameos, in the most general sense of the word, can be made of so many various things - hand
carved shell, hand carved agate, ultrasonically carved agate, poured "agate", coral, mother of pearl, turquoise, moulded resin, glass, painted porcelain, etc. The most popular cameos however are shell
cameos and blue/black agate cameos.

Cameos can be carved in relief or intaglio. In relief is the most established and means that the surrounding material is cut away from the image being carved, allowing the image to project above the surface. Intaglio means that the image is carved into the stone, so that it is below the surface level. When intaglio is done on a stone, the smooth surface of the top of the stone is carved. When intaglio is done on a piece of glass, the bottom surface of the glass is "carved" and usually painted, leaving the top of the glass smooth.

The most popular cameos today are carved in sea shells, a tradition that began in the 15th or 16th century and was popularised by Queen Victoria of England. Since that time, cameos have predominately showcased women's profiles, and been worn by women who enjoy the attractiveness and craftsmanship of hand-carved cameos.

Women began collecting cameos to prove cultural position during the Elizabethan period. At the same time, tourist travels to the ruins of Pompeii were on the rise and women began collecting shell and lava cameos as souvenirs to remember their travel.

During the 18th century, men purchased carved gems to mark their status and culture.
Cameos charmed Napoleon, who wore a cameo to his own wedding and founded a school in Paris to teach the art of cameo carving to young apprentices.
Not until the 19th century, when the reputation of shell cameos grew — reducing the use of hard stones or agate — did profiles become as popular a subject matter as they are today.

Cameos are pieces of art, and must be cared for therefore. Store your cameo away from heat or brilliant lights, in a softly lined box, and remember that simple cleaning is probably the best method:

Dust your cameo frequently with a soft brush.
While dusting, pay attention to the deep ridges in the cameo where dust is likely to gather. Dust can scratch a cameo, so it is imperative to keep it as dust-free as possible.
After dusting you may rinse a shell cameo with warm water, drying it afterward with a soft cotton cloth. Shell cameos are easily damaged, so avoid using soap, harsh cleaners or commercial jewelry cleaners.
Mother-of-pearl cameos can be cleaned with a mixture of mild soap and warm water before being dried with a soft cloth