Identification between natural pearls and cultured pearls

Natural pearl and cultured pearls both grow inside oysters. When a piece of sand or dirt gets into an oyster's shell, the animal coats the intruder with layers of a material called nacre in order to avoid irritation and then made natural pearls. However, cultured pearls are formed in oysters by humans to stimulate pearl production.
Brown ring of cultured pearls
After people stimulate the oyster, the nacre started to form around a cultured pearl, there will be a thin and brown ring if you put the pearl under intense light. That is not present in natural pearls.
Using X-ray
Nowadays, people can use X-ray to identify natural pearls. When you make pearls in X-ray exposure, the center of a cultured pearl is perfectly round while the center of a natural pearl is irregular in shape. The reason of this situation is that natural pearl was formed around a piece of debris rather than a bead.
Pearl price
Natural pearls are considered as the gift of nature, so the price of natural pearls is higher than cultured pearls. Natural pearls are priced by weight and cultured pearls are priced by diameter. When you buy pearl beads or pearl jewelry, you should open your eyes to identify.
Misconceptions of cultured pearls
Many people think that cultured pearls are fake pearls. In fact, cultured pearls are not fake or artificial because they are made by oysters through the same process as natural pearls.