The formation of shell is a biomineralization process, that is, a molecular manipulation process in which a small amount of organic macromolecules are used as templates and highly orderly combined to form organic substances.
Studies show that shells are mainly composed of inorganic phase and organic phase. Inorganic phase is 95 ~ 99.9% CaCO3 (calcite, aragonite, aragonite and amorphous). At the same room temperature, calcite is the most stable, aragonite is relatively stable and aragonite is the most unstable among the three crystal forms.
The organic phase consists of about 0. 1 ~ 5% organic matter (protein, glycoprotein, polysaccharide, chitin and lipid, etc.). ), which can be mainly divided into acid (water or EDTA) soluble components, acid-insoluble denaturant soluble components and acid-insoluble denaturant insoluble components. Further research shows that shells mainly contain elements such as calcium, carbon, oxygen, hydrogen, strontium and magnesium, and the contents of strontium and magnesium are mainly related to the species of shellfish.
Extended data:
Natural pearls are crystal blocks formed by shells in the natural environment. When mussels eat at the bottom of the sea, their shells open, sand, parasites and other foreign bodies occasionally fall in, and the mantle is stimulated, so they secrete nacre, wrap the falling foreign bodies layer by layer, make them smooth, and gradually form a pearl sac-a bright and moist outer layer.
According to this principle, cultured pearls are formed by inserting round beads into mussels by nuclear insertion technology.
Pintada is the general name of pintada. China has a history of collecting, fishing and utilizing pearl oyster for more than 2000 years. Since 1970s, Pinctada fuciformis and Pinctada maxima have been cultured on a large scale in the south coast of China, and good results have been achieved.
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