1. color: various colors on the surface of jewelry and jade.

2. Optical characteristics: refers to various phenomena caused by materials acting on the direction and propagation direction of incident light. Including the uniformity, inhomogeneity, anisotropic body axis and positive and negative optical properties of materials.

3. Refractive index and birefringence: The ratio of the propagation speed of light in air (or vacuum) to that in jewelry and jade materials is the refractive index, also called refractive index. The biggest difference between two or three principal refractive indexes in an anisotropic body is birefringence, also called refractive index (or refractive index). The refractive index of air is N= 1 (the refractive index is represented by n).

4. Absorption spectrum: refers to the spectrum generated by selective absorption when continuous spectrum light irradiates jewelry and jade materials.

5. Transparency: refers to the degree of light transmission of jewelry and jade materials, which can be sequentially: transparent, sub-transparent, translucent, slightly transparent and opaque.

6. Gloss: the ability and characteristics of the material surface to reflect light. According to the strength of luster, it can be divided into metallic luster, semi-metallic luster, diamond luster and glass luster. The special luster caused by aggregate or surface features includes grease luster, pearl luster, silk luster and so on.

7. Quality measurement unit: According to the types of jewelry and jade, the following measurement units are generally adopted, namely carat, gram, kilogram, etc. For example, the unit of measurement for diamonds is carats (or minutes), 1g (g) =5 carats (CT), 1g (CI) = 0.2g (g) = 200MG (mg). The smaller unit is minutes, 1 carat (CT)= 100 minutes. Pearls are measured by pearls (the diameter of round pearls is larger) and pearls (1 carat =4 pearls). Another example is high-grade hetian jade, the finished product is in grams and the raw material is in kilograms.

8. Density: Density refers to the mass of matter per unit volume. The unit is grams per cubic centimeter (g/cm3).

9. Hardness: Hardness refers to the ability of jewelry and jade to resist external mechanical effects such as scoring, extrusion or grinding. The hardness is usually expressed by Mohs hardness, and the relative hardness of minerals can be divided into 10 grades: 1 talc, 2 gypsum, 3 calcite, 4 fluorite, 5 apatite, 6 orthoclase, 7 quartz, 8 topaz, 9 corundum, and 10 diamond. Hardness test is generally not used as a routine appraisal item because it has slight damage to the tested object.

10. Internal and external features: External features refer to the external features of natural jewelry and jade, the former refers to the special phenomena related to crystal structure, and the latter refers to the phenomena left in the process of cutting, grinding and polishing. Intrinsic characteristics refer to the characteristics related to the growth environment and crystal structure preserved during the growth of jewelry and jade. Intrinsic characteristics are very important, which is an important basis for distinguishing natural and artificial products.