By about 1600, Anselmus de Boot noted that beginning with the shell pearl jewelry in the structure of similar appearance, but after about 100 years, researchers have cut pearls, and the actual shellfish, after the French scientist Rene Reaumur through their cut Slice placed under the microscope observation, found that pearl shells structure is similar to the material, consisting of layers of focus.

To have the past three centuries of the 20th century, the pearl jewelry industry has undergone tremendous changes, from the all-cultured pearls replaced the natural wild pearls.practice is the sole criterion for testing truth, through the 20th century the practice of cultured pearls , pearl completely resolved the issue of the formation. Now have ample evidence and sufficient reasons for the formation of pearls is that pearl shellfish to external stimulation of, secrete pearl quality, a package external layers of the results. Pearl formation of the issue is resolved, what is the pearl of the problem will be solved.

Japan nearly a century of pearl farming practice, and has accumulated rich experience, therefore, of what is called the pearl, we adopted the definition of Japan.

Japan's pearl of the Pearl made the following definition: Pearl is living in the pearl shellfish formed within the spherical or hemisphere-shaped (or somewhat deformed) things, is a product of metabolism, and it is the appearance of visible part of beads.

This definition of the formation of the location of pearl, pearl's mother-rearing and pearls, and other shapes made stringent requirements. The "metabolism" of this process is the key. Thus put a distinction between genuine and fake pearls have come. Also pointed out that cultured pearls and natural pearls are real pearls. Apart from the "pearl", including artificial imitation pearls, pearls are false. That the definition of quality pearls, mother-of-pearl that is secreted by the shellfish material, it is notable thin, very thin this thin, can only be measured in microns, the different colors of pearl quality, not its thickness equal, from 0.38 μ m to 0.45 μ m. Different climate different from the waters humidity, the number of pearl production is also inconsistent, the general daily production two to four times, each pearl production of more than 0.3 μ m thick. Cultured pearls thickness of the year only about 0.3 mm to 1 mm thick to a long, we need about three years, in other words, farming three years, there is Melaleuca on the pearl quality, so that could be used pearl beads in recent years of liquid spray system from the imitation pearl distinguish it from, so this definition offer pearl distinguish a legal evidence.