Recently, Guangdong Jewelry and Precious Metals Testing Center found some fakes in a gold jewelry building to remind investors to discern carefully. For example, the most outrageous is a fake jade, the glass production cost is only 20 yuan, and the price difference between the same size and true jade is 3,000 times. Experts remind customers to buy jewelry, precious stones and precious metals, remember to ask for a certificate of inspection, or ask a third-party testing agency to verify the body.
According to the relevant personnel of the testing center, in the recent market testing, it was found that some of the thousands of gold and gold jewelry were filled with too much flux, and the purity of the welding position was insufficient, resulting in insufficient overall purity of the jewelry. For every gram less, consumers lose about 300 yuan. If the consumer discerns carelessly, buying a fake diamond will cost a lot. Liu Zhenhua
Dye is an organic substance that enables the coloring of fibers and other materials. Dye a wide range, according to the source can be divided into natural dyes (such as plant dyes, animal dyes and mineral dyes, etc.) and synthetic dyes (or artificial dyes). According to the molecular structure can be divided into azo dyes, anthraquinone dyes, phthalocyanine dyes, aromatic methane dyes, nitro dyes and so on. According to the application method is divided into acid dyes, alkaline dyes, sulfur dyes, reactive dyes, disperse dyes, direct dyes and so on. Dye has a color, but the color of the material is not necessarily a dye. Dyes must have chromophores and help chromophores. The dye in the ink should also have a water-soluble group such as a sulfonic acid group.
Natural dyes are dyes obtained from animals, plants and minerals. According to the source can be divided into: â‘ plant dyes, from some plants roots, stems, leaves and fruits extracted from the dye, such as extracted from indigo indigo (blue), extracted from turmeric curcumin (yellow (Dinar), etc.); (d) dyes, extracts from the animal's body, such as carmine extracted from the cochineal, etc .; (d) mineral dyes, dyes extracted from the colored non-ferrous minerals of minerals , Such as chrome yellow, ultramarine, manganese brown and so on. Because of the natural dyes and artificial dyes compared to the existence of many shortcomings, such as incomplete chromatography, application inconvenience, poor fastness, in addition to a few still use, the majority was eliminated.
Synthetic dyes, also known as "artificial dyes". Mainly by the coal tar (or oil processing) fractionation products (such as benzene, naphthalene, anthracene, carbazole, etc.) by chemical processing, sometimes called coal tar dyes. As the first few kinds of synthetic dyes made of aniline as raw materials, it is also known as "aniline dye." Compared with natural dyes, synthetic dyes and more types, chromatography complete, most colorful, washable and durable, and can be mass production. So the current so-called dye almost all refers to synthetic dyes. The dyeing products are one of the common forensic materials.
Pigment is a colored, black, white or fluorescent particulate organic or inorganic solid. In water, oil or other application medium does not dissolve, but can be evenly dispersed, and in the entire dispersion process from the physical and chemical effects of the media, still retain its unique crystal or particle structure. According to the chemical composition of inorganic pigments and organic pigments; according to the color is divided into white, red, yellow, black and other pigments; according to the source is divided into natural and synthetic pigments, natural pigments are mineral (inorganic) such as He Shi, cinnabar, , Realgar, etc., there are animal and plant (organic) such as rattan, cochineal red, synthetic pigments are also inorganic and organic two categories; according to the use of coloring pigments, physical pigments and functional pigments. Coloring pigments are inorganic and organic pigments that impart various colors to the application medium. The pigment is a pigment that does not have a hue force and no hiding power. It is mainly used to reduce product cost and improve the performance of paint, plastic, rubber and other products. Called the filler. Now has been processed into ultra-fine grain of natural products and synthetic products, due to the synthesis of impurities in the small, fine particles and according to the need for artificial synthesis and a variety of surface modification, it can be used to reduce the hiding power of the pigment (Such as titanium dioxide) and improve product performance, and now it is called physical (incremental) pigments more appropriate, most of the main varieties of natural pigments are processed natural minerals such as natural calcium carbonate, barite powder, talc Such as precipitated calcium carbonate, precipitated barium sulfate, synthetic silica, etc .; functional pigments are pigments that give products specific functions, And change the color of the temperature paint, with poisonous biological function of the antifouling pigments, in the dark glowing luminous pigments, to prevent corrosion of rust-proof paint, pearl luster pearlescent pigments and so on.
Paint in paint, printing, rubber, plastics, paper, fiber, ceramics and other industries widely used, the product can be decorative, opaque, durable or special features.
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