The following is the noun explanation of the inspection items that are often seen on the jewelry appraisal certificate:
Color color
Color is the feeling produced in the brain by the response of the optic nerve of the fundus to light waves (visible light from 390nm to 780nm). After visible light is selectively absorbed by an object, the color produced by the mixing of its remaining light waves is the color of the object.
optical characteristics
It refers to various phenomena caused by substances acting on the direction and propagation direction of incident light, including homogeneity, heterogeneity, anisotropic body axis, positive and negative light and other characteristics.
Optical isotropic body isotropic material
An isotropic body refers to a substance whose optical properties are the same in all aspects. Equiaxed and amorphous materials are optically isotropic.
Optical anisotropic bulk anisotropic material
Refers to substances with different optical properties in all directions, which is called anisotropic body for short. Except for equiaxed and amorphous materials, they are all optically anisotropic.
Refers to the crystal has two special directions (two optical axes), when light is incident parallel to these two directions, birefringence does not occur. The crystals of orthorhombic system, monoclinic system and triclinic system are all biaxial crystals.
Refractive index
The ratio of the propagation speed of light in air (or vacuum) to that in gem 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).
absorption spectrum
Refers to the spectrum produced by selective absorption when continuous spectrum light irradiates jewelry and jade materials. In a narrow sense, it refers to the phenomenon that the spectrum produced by selective absorption in visible light (700-400nm) appears as black bands or black lines.
shine
The ability and characteristics of material surface to reflect light. According to the strength of luster, it can be divided into sub-metallic luster, semi-metallic luster, diamond luster and glass luster. The special luster caused by aggregate or surface features are: greasy luster, waxy luster, pearl luster, silky luster and so on.
Transparency transparency
Refers to the transparency of jewelry and jade materials. Can be divided into: transparent, translucent, translucent, translucent, opaque.
Ultraviolet fluorescence
Refers to the visible light waves produced when ultraviolet rays irradiate jewelry and jade. According to the intensity of light, it is divided into: strong, medium, weak and none.
Flame color dispersion value flame
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 fire color intensity) of the reflective material. Theoretically, it is expressed by the difference of refractive index between red light (B=686.7nm) and violet light (G=430.8nm). 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 in a unit volume. The unit is grams per cubic centimeter.
difficulty
Hardness refers to the ability of gem materials to resist external mechanical effects such as scratches, squeezing or grinding. The hardness of gemstones is expressed by Mohs hardness in mineralogy.
Split, fracture, separation
Cleavage refers to the property that a crystal splits into a smooth plane along a certain crystallization direction under the action of external force. 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 a crystal breaks along a certain crystallization direction (such as the junction of twins) under the action of external force.
Internal characteristics
It refers to the solid, liquid and gas inclusions contained in gem materials, special types of inclusions (such as negative crystals) and phenomena related to the crystal structure of gems. Such as: growth line, ribbon, winding, cleavage, cleavage, etc.
External character
The external characteristics are divided into the external characteristics of crystals and the external characteristics of cut stones.
The external characteristics of crystals refer to special phenomena related to crystal structure, such as transverse crystals, longitudinal crystals, twins, growth pits, erosion and hillock dissolution, in addition to the shape, color, transparency and luster of crystals.
The external features of cut gemstones refer to the phenomena left in the process of cutting and polishing, such as scratches, polishing lines (marks), micro-notches, holes, damage, burn marks, impact marks, whiskers, extra facets, sharp or smooth edges, etc.
Optimization processing enhancement
All methods used to improve the appearance (color, clarity or special optical effects), durability or usability of jewelry and jade except cutting and polishing. It is divided into two categories: optimization and processing.
Optimization enhancement
Traditional, widely accepted and optimized treatment methods show the potential beauty of jewelry and jade.
Treatment treatment
Non-traditional and not yet accepted optimization treatment method.
Common optimization methods
Optimization methods: heat treatment, bleaching, wax dipping, colorless oil dipping and 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.