1, the appearance is different. Oysters are made from oysters. Impurities attached to the shell are removed, dried, broken into small pieces, and the dust is removed for later use. Calcined oysters are roasted to grayish brown on fire on the basis of raw oysters. Raw oysters are sapphire or grayish yellow, or gray, with uneven surface, while calcined oysters are grayish white, occasionally blue-gray or grayish yellow, with a slight burnt smell. This is the difference between raw oysters and roasted oysters in processing and appearance.

2. The efficacy and function are different. The difference between oysters and calcined oysters is that oysters are mainly used for calming the nerves and nourishing yin, softening and resolving hard mass, especially for insomnia, tinnitus and cough. Calcined oyster is mainly used for relieving pain, treating night sweats, improving nocturnal emission and metrorrhagia, and has a good effect on improving pantothenic acid in stomach diseases.