Cypraea Tigris, i.e. Tiger Shell is 2-4 inches in length and height. It has seven different layers of color. In order: tiger brown on the surface. then white-yellowish, grey-blue, two tones of purple and finally a slightly bluish white color. It is found in the Indo-Pacific.
Cypraeacassis Rufa Shell, i.e. Carnelian Conch Shell is about 6 inches in height and length. Has an interior reddish-brown layer and the exterior for engraving is a pale flesh with peach and orange hues of color. They are the most frequent shells used for cameo carving. Carnelian conch shells are most often fond off the coast of West Africa.
The most common materials used for cameos are shells known as: Sardonyx shell (Cassis Madagascariensis), Carnelian shell (Cassis Rufa), Pink shell(Strombus Giga), Tiger shell (Cyprea Tigris), Lava, Coral, and Turquoise.
Casco cameos, llc.
Strombus Giga, i.e. Pink shell, is about 11 inches in height and length. Found in the Caribbean sea, Bermuda, Bahamas, Brazil, and the gulf of Mexico. Its white and it's pink layers are not always distinct from one another; also used in necklaces, buttons, etc. It also can be found with an orange color as well.
Cassis Madagascariensis, i.e. Sardonyx Shell is about 12 inches in height and length, chestnut brown in color on the inside and perfectly white on the outside. It is native to Bermuda, Venezuela, West Indies, and the United States. It is a rare so it is expensive and is ideal for carving relief cameos.