1, scorpion, magnifying glass: This is a small equipment regardless of jewelry research, identification workers, or jewelers are essential and can not be less. But you can really use it effectively and accurately. It is also important to rely on practical experience. 1) Scorpion: There are slots and no grooves in the middle of the front, but there are two kinds of horizontal stripes. When shooting a gemstone, the gemstone is generally held by the left hand and the magnifying glass is held by the right hand, but each person can operate according to the habit. The photostone should be too tight or too loose, and should be held parallel to the gemstone 3 waist. 2) Magnifying glass: There are lenticular lenses, double combined mirrors and triple combined mirrors in various forms, different magnifications of magnifying glasses. Commonly used in the jewelry industry is the 10X standard three-combination mirror - that is, a pair of convex lenses and two meniscus lenses. The advantage is that the viewing area is wider, which can reduce image distortion and color edge phenomenon. The role of the magnifying glass: mainly used to observe the surface and internal features of the gemstone: 1 surface - including the basic properties of the gemstone and processing quality, such as gloss, faceted edges, surface smoothness, original crystal face cleavage, fracture, Overall cutting and polishing quality and so on. 2 internal - including ribbon, growth pattern, rear facet edge ghost and color body. 2, microscope: the advancement of human science and technology, the manufacture of a variety of microscopes, they have their own specific kinetic energy and uses, such as medical microscopes, biological microscopes, rock mineral microscopes and some special large optical microscopes. The jewelry industry currently uses a vertical binocular stereo zoom microscope with a bottom light source. Such a microscope can be used to study the internal and external features of the gemstone, and to study the internal structure of the minerals and the like. 1) Basic structure of the microscope: 1 frame, 2 eyepieces, 3 zoom system, 4 objective lens, 5 bottom light source, 6 adjustable focal length system, 7 fiber optic lamp, 8 photomicrography system. 2) The application should understand and master several necessary operation methods: 1 dark-field illumination method--that is, the light from the bottom light source is not directly directed to the gemstone, but is reflected by the hemispherical reflector and then to the gemstone. The advantage is that since the light does not directly enter the objective lens barrel, the chromatic body of the colored body causes the light to scatter, which helps the light to enter the objective lens, so that the inner and outer features of the gemstone are very clear on a dark background. 2 bright field illumination method - that is, remove the light barrier, the light from the bottom light source directly hits the gemstone. This method facilitates the study of the gemstone's ribbon, growth lines and low solid color bodies. 3 top light illumination method - that is, only the top light source is used for illumination, and the light is reflected by the gemstone into the field of view. (This is a kind of operation similar to a reflective microscope), which facilitates the observation of gemstone surface, superficial and near-surface features (such as the observation of the dissolution wave of B jadeite). 4 observation of water immersion and oil immersion - the gemstone is immersed in water or a special liquid to observe its internal characteristics, this method is beneficial to eliminate the reflected light of the gem surface and the study of small faceted gemstones (especially Synthetic gemstones observe the color of the ribbon). 3) Use and use of the microscope: 1 use and adjustment: adjustment: a, adjust the eyepiece to make the left and right field of view overlap. (You can adjust the center of the field of view by placing a black dot on a piece of white paper). b, the focus distance is adjusted, and the adjustment is clear. Use steps: a, clean the gemstone; b, observe cleavage, fracture, growth and other characteristics at low magnification; c, adjust the internal and external features of interest to the center of the field of view to increase the multiple observation. Even under different conditions, such as bright areas, dark areas, observation under top light, and observation in water immersion and oil immersion; d, spectacles after observation - this is a kind of birefringence, three Refraction or single-refraction gemstone research is a fast and effective method of observation. For example, the olive stone has an obvious rearward ridge, and the emerald cannot have a distinct rear rib. This is easy to distinguish. How to operate? Under the condition of 10 times, observe the image of the ribs away from the edge of the objective lens, the color body, the wave, etc., and observe that the line of sight should pass through the same facet to prevent the surface of the facet from producing false double images. Rotating gems should be observed from three aspects to avoid parallel optical axis directions. Polarizer observation can be added to ensure accuracy. 2 The use of the microscope can be observed: a. gem surface characteristics; b. gem internal characteristics; c. determination of approximate refractive index; d. photomicrography; e. observation of chromaticity, interference pattern; 3. Refractometer: Refractometer This is one of the most important instruments in jewellery research. 1) Production principle: It is manufactured according to the refractive index formula and the principle of critical angle and total reflection angle. 2) Structure and working principle: 1 structure: mainly composed of high refractive index prism, prism mirror, lens, eyepiece and so on. In addition, the necessary high-definition solution and ideal light source. A. High-refractive-index prisms should have two conditions: single refraction, high refractive index, currently used high-alumina glass, cubic zirconia as material. B. Intercalation solution: Its function is to make a good optical connection between the gemstone to be tested and the high refractive index prism (otherwise there is an air film to prevent contact). Commonly used diiodomethane dissolved sulfur (saturated) to add 18% tetraiodoethylene, RI = 1.80-1.81. C. Light source: There are two kinds of external and internal light, and the ideal light source is yellow light with a wavelength of 589.5 nm. (sodium light) 2 Working principle: the gemstone is a light sulfur medium, the prism and the solution are optically dense media: A. When the incident angle is less than the critical angle, the light is refracted into the gemstone. B. When the incident angle is greater than the critical angle, the light is totally reflected, that is, returned to the prism and passed through the refractometer scale, and then reflected by the mirror to change the direction of light propagation, so that it enters the human eye through the eyepiece to form a bright region. C. The light that is refracted into the gemstone cannot be observed by the human eye to form a dark area. D. The shadow boundary of the bright and dark junction marks that the light is incident at a critical angle - that is, the refractive index value of the gem being tested. 3) How to use: 1 Myopia method, also known as facet method - operation steps: A. Clean the gemstone, turn on the light source, clean the prism and the countertop. B. Set the stone on the metal table. C. Tap the droplet contact solution in the center of the prism. D. Push the gemstone into contact with the solution in the center of the prism. E. Observe the light and dark condition of the ruler in the field of view. F. Light special gemstone 360 ​​degrees, once every turn and then observe the record. G. Clean the gemstones and prisms after work. 2 Farsightedness, also known as the sputum method, is suitable for curved and small faceted gemstones. Method of operation: A. Drop a small drop of contact solution on the metal table. B. Holding the gemstone, contact the contact liquid with its curved surface (or smooth surface) so that the oil droplet diameter is about 0.2 mm. C. Place the gemstone in the center of the prism. D. Eyes are 30-45cm away from the eyepiece. Move the head back and forth (or up and down) parallel to the eyepiece. Observe that the oil droplets are ellipsoidal and semi-dark, and the number of turns in the high boundary is recorded. 4) Observation of phenomena and conclusions: 1 Rotate the gem 360 degrees, a shadow boundary appears in the field of view. If the polarizer disposed on the eyepiece is quickly rotated, the shadow boundary does not jump up and down, indicating that the gemstone is a field mass or an amorphous gemstone or a polycrystalline aggregate gem. 2 Rotate the gem 360 degrees, two shadow boundaries appear, one of which keeps the reading unchanged during the rotation of the gem, indicating that the gemstone is a single crystal. 3 Rotate the gem 360 degrees, two shadow boundaries appear, and the two shadow boundaries move with the gemstone rotating surface, indicating that the gemstone is a biaxial crystal. 4 Rotating the gemstone 360 ​​degrees, the entire field of view is dark, only the shadow boundary of the 1.81 formed by the refractive oil can be observed, and the gemstone is observed by the far vision method, indicating that the gemstone refractive index is larger than the contact liquid--called " Negative reading". Other special phenomena may occur, such as: A. False homogeneous body. B. False one-axis crystal. C. Special optical orientation. D. Some special bi-fold gems. 4, UV fluorescent light Ultraviolet fluorescence is used to identify jewels and jade, which is very meaningful. Ultraviolet light refers to the part of the electromagnetic spectrum of 400-10 nm, which is located between visible light and incident light. The fluorescence and phosphorescence involved in the previous section are the result of working under UV light. 1) Principle: Ultraviolet light is emitted from a lamp that supplies an ultraviolet light source, and after a special filter, only a long wave (Lw) having a main wavelength of 365 nm and a short wave (Sw) ultraviolet light having a wavelength of 253.7 nm are emitted. 2) Uses: 1 Help identify gemstone varieties, such as: red garnet: Lw: none, Sw: none. Ruby: Lw: bright red, Sw: dark red. Zircon: Lw: yellow, Sw: yellow. 2 help identify gems and synthetic gems. 3 help identify diamonds and imitations. 4 help to determine whether the gemstone has been manually processed. The ultraviolet fluorescence intensity is divided into four expressions: strong, medium, weak, and no. 5, polarizer 1) Structure and principle: 1 is mainly composed of three polarizers, in addition to a light source, a glass table and an interference lens 2 Principle: A. When the natural light passes through the polarizer, the pupil plane is polarized. If the up and down polarization is parallel, the brightness is the largest, and the up and down polarization is the darkest, and the field of view is the darkest. B. Heterogeneous gemstones have the ability to decompose light into two mutually perpendicular polarized lights. It can change the polarization direction of incident light. C. The polarized light incident along the optical axis of the heterogeneous body will no longer decompose. D. Two mutually polarized light will block the passage of light. 2) Application: Polarizing mirrors play an important role in the identification of homogeneous, heterogeneous and polycrystalline bodies. 1Homogeneous body--Natural gloss When the polarizer passes through the gemstone, the direction of vibration of the light does not change. When the upper polarizer is passed, all of it is blocked and cannot pass, and the rotating gemstone is completely extinguished. 2 non-homogeneous body--rotating gemstone under orthogonal polarized light appears four bright and four dark phenomenon. Principle: Heterogeneous gemstones have the ability to decompose light into two beams of light that are perpendicular to each other. When the light enters the gemstone to be tested through the plane polarized light of the lower light piece, the gemstone is decomposed into two polarized lights whose vibration directions are perpendicular to each other. As the gemstone rotates, the two polarized vibration directions that are decomposed also rotate, so that when the depolarized polarized light appears, it is completely blocked by the upper polarized light, and then completely passes through the phenomenon of light and dark alternating, and appears four times a week. However, if the direction of the optical axis of the gem is flat in the viewing direction, this phenomenon does not occur, but is completely dark. 3 polycrystalline gemstones - under orthogonal polarized light, the gems are fully illuminated. This is because a large number of crystals in the polycrystalline aggregate are disorderly arranged, and thus the polarization direction of the polarized light generated by the decomposition of the light of the different crystals is also disorderly and approximates white light. 4 Special phenomena: A. Abnormal metering: Some homogenous gemstones (such as garnet) are not completely dark under the microscope but appear bright and uneven. This is due to the occurrence of abnormal birefringence in the crystal. Caused. For example, garnet is not caused by the heterogeneity of the lattice due to the substitution of the isomorphism. B. Full dark illusion: such as some high-refraction gemstones, such as zircon, c2..., at this time, the bright part of the face can be placed on the stage for observation. 6, two-color mirror: 1) Principle and structure: 1 Principle - Natural light enters a heterogeneous gemstone and is decomposed into two polarized lights whose directions of vibration are perpendicular to each other. The two beams of light each have a different direction of propagation. The anisotropy of non-homogeneous gemstones results in different absorption of light in different vibration directions, resulting in different colors. We separate the two vibrating lights and see different colors. A dichroic mirror is the instrument that does this. 2 structure--the commonly used dichroic mirror is the ice continent stone dichroic mirror, which is composed of: a, glass prism; b, ice continent stone body; c, light window and eyepiece. Due to the strong birefringence (DR=0.162) of the ice stone, the window (W) appears double shadow. When observing a pleochroic gemstone, the ice stone dichroic mirror will again decompose through the two polarized color lights of the gemstone, causing them to appear side by side in the two window images. 2) Application: 1 The homogeneous gemstone is not anisotropic, so there is no pleochroism, and the amorphous material is also not polychromatic. 2 Non-homogeneous gemstones: A. Only when the two polarized light vibrating directions passing through the gemstone are parallel to the direction of light vibration passing through the ice stone rhombohedron, what is seen is the true pleochroism color of the gemstone. B. When the light passing through the gemstone intersects the vibration direction of the light passing through the dichroic mirror at 45 degrees, no dichroism is observed. Intersected at other angles, it is still a mixed color, not a true pleochroic color. When the optical axis of the gemstone is parallel to the long axis of the dichroic mirror, pleochroism is also not seen. Therefore, we must constantly rotate the gemstone and observe the orientation while observing the gem. C. Polychromaticity occurs in colored heterogeneous gemstones. 3 The chromaticity of gemstones is divided into strong, medium, weak and no. But often to describe its color, such as ruby ​​is often described as red-orange. 4 dichroic mirrors can help identify gemstone varieties or synthetic gemstones. Such as: ruby ​​and garnet and synthetic ruby, green tourmaline and olive stone. 5 can help and align the color of the gemstone to facilitate cutting. 6 can be used as an auxiliary identification method to help identify gems. 3) Note: 1 Cannot use monochromatic light, polarized light to observe, but apply white light and transmit. 2 Gems should be colored non-homogeneous gemstones. 3 Gems should be close to the dichroic window and constantly rotating the gemstone to observe. 4 pleochroism has nothing to do with the bi-fold rate. Business Cotton Socks,Men'S Business Socks,Men'S Business Cotton Socks,Breathable Business Cotton Socks Jingjiang Pingdong Import&Export Co.,Ltd , https://www.jjpdsocks.com