Step 1: Logo (the certificate also depends on the logo). We can confirm through the logo on the certificate that the testing organization that issued the certificate is approved by those special qualification certifications. Generally, the logo that appears on the certificate is "CMA". "CMA" is the English abbreviation of ChinaMetrologyAccreditation. It is a comprehensive certification and evaluation of the testing ability and reliability of testing institutions by the metrological administrative department of the people's government at or above the provincial level according to the provisions of the People's Republic of China and the National Metrology Law. This sign only means that the institution is a unit that has passed the measurement certification review, and it is a necessary qualification for any unit that issues a jewelry appraisal certificate. The inspection report marked with "CMA" can be used for product quality evaluation, results and judicial appraisal, and has legal effect. Step 2: Appearance description (check the model and observe the sample) The next step is to confirm whether the purchased jewelry and jade are consistent with the sample described in the certificate, including: the photo of the sample, the weight on the label and the weight on the certificate, and whether the appearance and description of the jewelry correspond to each other. Photos are the direct evidence to distinguish different jewels and jade, and the identification certificate photos are clear and accurate, which will greatly increase the difficulty of forgery. However, in some cases, it is difficult to distinguish because the jewelry styles are similar and the photo features are similar. In this case, the accurate weight is another valid data that can be verified. In addition to photos and weight, the appraisal certificate will also provide some distinctive appearance features, such as the sugar color of jade, the size of bracelets and so on. Step 3: Test the content (the most important content). This step should be our most concerned test content, and we should know which content on the certificate is the most important. Grading certificate of inlaid diamonds: The most important thing to pay attention to is the color grade and clarity grade of diamonds, and some certificates also have the cut ratio of diamonds. Purity inspection certificate of precious metal ornaments: the most important thing is of course the type and content of precious metals. Jewelry and jade appraisal certificate: the inspection conclusion is the most important. According to the national standards, natural jewelry and jade are no longer marked with the word "natural", but the artificially treated or artificially synthesized gems must be clearly stated, such as: the conclusion is "ruby", indicating that this ruby is purely natural; "Ruby (treatment)" indicates the specific treatment method, indicating that this ruby is a natural gem, but it has been artificially treated in some way to improve its appearance; "Synthetic ruby" means that ruby is not naturally produced, but a purely artificial laboratory synthesis. "Remarks" column: Generally, some relatively special samples are encountered in the testing process, which will be explained in the remarks. For example, in the appraisal certificate of Hetian jade, once the surface treatment is involved, the specific treatment method will be indicated in the remarks. Step 4: Official seal or inspection mark In order to prevent the certificate of appraisal institution from being counterfeited, the appraisal certificate must be stamped with the official seal of the unit, and the red official seal is used as the inspection mark, which is often not printed integrally with the certificate, but stamped after inspection. Nowadays, some large authentication machines are carrying out heavy anti-counterfeiting. For example, Xinjiang Rock and Mineral Gem Quality Inspection Station has added an online query function in the new certificate launched in 27. When inquiring, you need to enter the batch verification code and enterprise verification code, so that consumers can verify it in a convenient way and find out the relevant information of the jewelry and jade purchased online. Step 5: Understand that the standard general appraisal certificate will also indicate the criteria for the identification of jewelry and jade. The current national standards specifically include: GB/T16552 Jewelry and Jade Name; GB/T16553 jewelry and jade identification; GB/T16554 diamond classification; GB/T1843 Nondestructive testing method for precious metal jewelry content: X-ray fluorescence spectrometry; GB11887 Rules and naming methods for purity of precious metals in jewelry. If you see that the certificate has one or two of these standards, you can know what standards jewelry and jade are tested according to. In addition, the certificate should also have the signatures of more than two appraisers and the appraisal date of the certificate. After understanding these five parts, whether your favorite baby is true or not and whether the certificate is consistent will come to the bottom. Step 6: Understand the basic knowledge The following is the noun explanation of the inspection items that are often seen in jewelry appraisal certificates: Color colour is the feeling produced in the brain by the optic nerve of the fundus of the eye in response to light waves (visible light from 39nm to 78nm). Visible? After being selectively absorbed by an object, the color produced by mixing the remaining light waves is the color of the object. Opticalcharacter refers to various phenomena caused by materials acting on the direction and propagation direction of incident light, including homogeneity, heterogeneity, non-isotropic body axiality, positive and negative optical characteristics of materials. Optical isotropic body isotropicmaterial refers to a substance whose optical properties are the same in all aspects, which is called isotropic body for short. The equiaxed and amorphous materials are optical isotropic body. Optical non-isotropic body anisotropicmaterial refers to substances with different optical properties in all directions, which is called non-isotropic body for short. Except for equiaxed and amorphous materials, they are all optical non-isotropic body. Refers to a crystal with two special directions (two optical axes) and no birefringence when light is incident parallel to these two directions. The crystals of orthorhombic system, monoclinic system and triclinic system are biaxial crystals. Refractiveindex,birefringence The ratio of the propagation speed of light in air (or vacuum) to that in gem materials is refractive index, also called refractive index. The maximum difference between two or three principal refractive indexes in non-isotropic body is birefringence, which is also called refractive index (or refractive index). Absorptionspectrum refers to the spectrum produced by selective absorption when continuous spectrum of light irradiates jewelry and jade materials. In a narrow sense, it refers to the phenomenon that the spectrum produced by selective absorption in the visible light (7-4nm) appears as black bands or black lines on the spectrum. The ability and characteristics of reflecting light on the surface of glossy luster material. According to the strength of luster, it can be divided into metallicluster, semi-submetallicluster, adamantine luster and vitreous luster. The special luster caused by aggregate or surface features includes: greasyluster, waxyluster, pearlyluster, silkyluster, etc. Transparency refers to the degree of light transmission of jewelry and jade materials. It can be divided into: transparent, semi-transparent, translucent, semitransparent and opaque. Ultravioletfluorescence refers to the visible light waves produced when ultraviolet light is used to irradiate jewelry and jade. According to the intensity of light, it is divided into: strong, medium, weak and none. Fire color fire,dispersionvalue When white light shines on a transparent faceted gem, the phenomenon that the gemstone shows spectral color flicker due to dispersion is called fire color. The dispersion value is the physical quantity of the dispersion intensity (that is, the intensity of fire color) of the reflective material. Theoretically, it is expressed by the difference between the refractive index of the material relative to red light (B=686.7nm) and that of violet light (G=43.8nm). The greater the difference, the greater the dispersion intensity (the stronger the fire color). Density The density of a gem refers to the mass of a substance per unit volume. The unit is g/cm3. Hardness Hardness refers to the ability of gem materials to resist external mechanical effects such as scoring, pressing or grinding. The hardness of gemstones is expressed by Mohs hardness in mineralogy. Cleavage,fracture,parting parting cleavage of fracture surface refers to the property that crystals crack in a certain crystallization direction under the action of external force and become smooth planes. Cleavage is divided into extremely complete, complete, medium and incomplete. Fracture refers to the nature of irregular fracture surface of crystal under external force. Common fracture types are: uneven, serrated, shell-like and so on. Cleavage is the property that crystals break along a certain crystallization direction (such as the junction of twins) under the action of external force. Internalcharacter refers to solid, liquid and gas inclusions, special types of inclusions (such as negative crystals) and phenomena related to the crystal structure of gemstones. Such as: growth line, ribbon, twine, cleavage, cleavage, etc. External characteristics External characteristics are divided into external characteristics of crystals and external characteristics of cut gemstones. The external characteristics of crystals refer to the special phenomena related to crystal structure besides crystal shape, color, transparency and luster, such as transverse grain, longitudinal grain, twin grain, growth pits, erosion and mound dissolution. The external characteristics of cut gemstones refer to the phenomena left in the process of cutting, grinding and polishing, such as scratches, polishing lines (marks), micro-notches, holes, injuries, burns and bumps. Marks, whiskers, extra facets, sharp or smooth edges, etc. Optimization treatment enhancement all methods used to improve the appearance (color, clarity or special optical effect), durability or usability of jewelry and jade except cutting and polishing. It is divided into two categories: optimization and processing. Optimize the traditional and widely accepted optimization treatment methods of enhancing to show the potential beauty of jewelry and jade. Non-traditional and not yet accepted optimization method to deal with treating. Common optimization methods: heat treatment, bleaching, wax soaking, colorless oil soaking, dyeing (chalcedony, agate). Treatment methods: immersion in colored oil, filling (glass filling, plastic filling or other hard materials such as polymers), immersion in wax (turquoise), dyeing, irradiation, laser drilling, film covering, diffusion and high temperature and high pressure treatment.