Shell molluscan wrap up theca has a special glandulose cell and the secretion of the cell can come into being calcify substance which can protect the soft part of the body. This is shell. The quantity, the shape and the structure of the shell are very different and always change.
    The main composition of the shell is 95% calcium and a spot of the chitin element. It has three layers. The outer layer is horniness layer (hull) which is black brown. It is thin and transparence and can prevent corrosion by the carbonic acid. It is formed by the chitin element. The middle layer is prism layer which is thick and formed by the calcite which is excreted by the brim of the wrap up theca. The outer and the middle layer can expand the proportion of the shell but can not increase the thickness of the shell .The inner layer is pearl layer (bottom layer) which is beautiful and brightly. It can increase thickness with the body increase.
    The shell powder not only contain a mass of calcium carbonate, but also have necessary microelements for the animal body, such as copper, magnesium, potassium, molybdenum, phosphor, manganese, iron, zinc and so on. In addition, it has much amino acid composition in the pearl layer of the shell.
The produce process of the shell power: classify, clean by water, clean by alkali, kibble, dryness, classification by air current mill.
    The shell powder mainly used in feed additive, environment protection fertilizer, cropper, medicine, top grade fitment dope, improve soil, ornament procession, the stuffing of the macromolecule material and so on.