Red coral is considered precious because it can be cut and polished like a gemstone and the natural colors ranging from pink to dark red are inherent to the skeleton of the marine creature. It has been harvested from shallow waters of the Mediterranean and traded for centuries; variants of the species are also found off the coast of Japan. Moh's hardness is around 4, which is harder than calcite but not as strong as most gemstones. Red coral is referred to as a branching coral, resembling leafless tree branches, with striations appearing parallel. Less expensive coral components include dyed sponge coral and bamboo coral, both of which are generally dyed red to resemble precious coral. However, the structure of sponge coral is much more open and porous than red coral, making it easy to distinguish. Bamboo coral forms in branch-like structures, similar to red coral, but it forms at much greater depths and lacks the inherent red cartenoid coloring. It is often dyed a deep bold red, which also tends to distinguish it from red coral.

Coral may be dyed other colors; the natural blue-gray color of sponge coral may be deepened and enhanced, and bamboo coral may be dyed a pleasing pink hue. Cupolini or cupolino coral refers to a thin, branch-like shape that is generally dyed and drilled through the center.

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