Touch the crystal with your hands, and the temperature in the rock crystal is usually much colder than that in the artificial crystal. Fu Lushou observed with his eyes that there are often cotton-wool inclusions in rock crystals, which are not found in artificial crystals. For monochromatic crystals such as amethyst and topaz, it is usually necessary to observe their dichroism, and even the top amethyst and topaz have chromatic aberration. This method can be used to identify whether to add color. These are the simplest methods and easy to understand.
Identification method
Visual observation: rock crystal is generally flocculent (cotton wool-like), commonly known as defects. This is a small hole for liquid to come out and carbon dioxide, but synthetic crystals have no such characteristics. The fineness of crystal has different grades, and there are many factors that affect the price of crystal. Unlike diamonds, you can judge them by 4C, so you need to listen more, watch more and compare more to really distinguish them. The general specification is that the larger the crystal stone, the more transparent it is, the more delicate its color and the more typical its shape. But the most important thing is that you like it yourself. There are roughly the following ways to identify the authenticity when buying: 1 Look: stone crystals are often affected by the environment and always contain some impurities. When you look at the sun, you can see tiny and even stripes or catkins. Fake crystals are mostly made of inferior crystal slag and glass slag. After polishing, coloring and imitation, there are no uniform stripes and catkin-like substances. Tongue licking: even in the dog days of hot summer, licking the appearance of rock crystal with your tongue will feel cold and cool. Fake crystals are not cool. Illumination: The crystal is placed vertically in the sun, which can emit beautiful light from any angle. Fake crystals can't. 4 hardness: the hardness of the crystal is very high, so it will be lightly scratched on the jewelry with gravel, leaving no trace; If there are streaks, it is a fake crystal. 5. Check with a polarizer: rock crystal with four bright and four dark changes when rotated 360 degrees under the polarizer, and false crystal without change. 6 check with dichroism: natural amethyst has dichroism, and fake crystal has no dichroism. 7. Examining with a magnifying glass: When examined with a magnifying glass of ten times under the transmitted light, the bubbles that can be found can basically be classified as pseudocrystals. 8 check with hair: only in a round crystal ball. Put a crystal ball on a hair. The crystal ball is the kind that the human eye can see the double shadow of the hair through the crystal. Mainly because the crystal has birefringence. However, it is impossible to distinguish natural crystals, cultivated crystals and melted crystals. Only other substances such as glass can be distinguished. 9. Test with thermal conductivity meter: set the thermal conductivity meter to 4 squares of green to test the gem, and the rock crystal can rise to 2 squares of yellow, while the false crystal does not rise, and when the area is large, it will rise to 1 square yellow.
The difference between crystal and glass
If the proportion of lead oxide in glass reaches more than 24% and the refractive index reaches 1.545, it can be called crystal. The variety of rock crystals is hexagonal columnar, rhombohedral and condensed, with horizontal stripes and twins on the conical surface and water droplets attached to the crystal surface. Piezoelectric crystals are rod-shaped, with special fish-scale growth lines, no crystals or twisted crystal buds with parallel cylinders at the center of the crystals. The glass is irregular in shape, and water droplets immediately spread on its surface. The cleavage fracture of crystal luster hardness is as clear as Mohs 7, without cleavage, conchoidal fracture, parallel fracture and obvious ridge. Piezoelectric crystal luster white 6.8-7 Shell fracture is incomplete. If the glass smokes, the color will be red 5.5-6. The fractures are parallel and the ridges are not parallel. The characteristics of inclusions in the variety are irregular inclusions and cotton-wool bubbles compared with those with heavier rock crystals. 2.56-2.66 Piezoelectric crystals have regular circular, elliptical or elongated regular debris inclusions and bubbles. 2.6 There are rare regular bubbles and inclusions in the left and right glass. 2-2.20, but the heavier variety of aluminum glass-crystal is obviously cooler, and the refractive index is 1.544- 1.533. Piezoelectric crystals have cold and light-sensitive characteristics similar to those of rock crystals, and their extinction speed is slower than that of rock crystals. The temperature-sensitive refractive index of glass is about 1.40, which is completely extinction. Optical glass cannot transmit light, but there is no extinction phenomenon.
Crystal and artificial crystal
Fashion collectors like to collect rock crystals, but they are often blinded by a large number of synthetic crystals on the market. Crystals on the market: fused crystals (synthetic crystals) are mostly made of quartz powder, glass slag and crystal waste. The hardness of molten crystals is generally between 5.5 and 6, so its hardness is lower than that of crystals. Crystal is 7-culture crystal: culture crystal refers to taking stone crystal as seed, and then applying high pressure to stone crystal to make it grow. There are molecules rich in silicon dioxide in the culture device. Then silicon dioxide molecules grow around rock crystals, so the crystal composition (molecular formula) is exactly the same as that of rock crystals, the only difference is that the magnetic field of this crystal is not as strong as that of rock crystals. The so-called Austrian crystal in PS is actually leaded glass. Generally speaking, adding lead to glass will make the color and transparency of glass better. How to distinguish between rock crystals and synthetic crystals? ① At first glance: During the formation of rock crystals, there are always some impurities affected by the environment. When observing the sun, you can see bright, uniform and tiny horizontal stripes or catkins. The fake crystals are mostly made of inferior crystal slag and glass slag, which are melted, polished and colored, without uniform stripes and catkin-like substances. ② Lick your tongue: Even in the dog days of hot summer, licking the appearance of rock crystal with your tongue will make you feel cold and cool. Fake crystals are not cool. ③ Illumination: The crystal is placed vertically in the sun, which can emit beautiful light from any angle. Fake crystals don't work. 4 Hardness: The hardness of the crystal is high, so it will be lightly scratched on the jewelry with gravel, leaving no trace; If there are stripes, it is a fake crystal. ⑤ Inspection with a polarizer: Rock crystals with four bright and four dark changes are rotated by 360 degrees under the polarizer, and pseudocrystals are unchanged. ⑥ Check with dichroism: natural amethyst has dichroism, while fake amethyst has no dichroism. ⑦ Examination with a magnifying glass: When examined with a magnifying glass of ten times under the transmitted light, the bubbles that can be found can basically be classified as pseudocrystals. ⑧ Check with the hair bundle: When the crystal is placed on the hair bundle, the human eye can see the rock crystal through the crystal, mainly because the crystal has birefringence. ⑨ Detection with thermal conductivity meter: Adjust the thermal conductivity meter to green 4 squares to detect gems, and the rock crystal can rise to yellow 2 squares, while the false crystal does not rise, and when the area is large, it will rise to yellow 1 square. Artificial crystals are divided into melted crystals and cultured crystals. According to crystal expert Xiao Moufeng, with the improvement of crystal value, more and more people like it, and crystal has also attracted the interest of counterfeiters. At this stage, the few methods of counterfeiting in China crystal market are: pictographic crystals: some crystals have vivid scenery, so don't look at the pictographic scenery in the crystals. Now many people have been fascinated by the use of AB glue, cut the crystal and add a landscape (small tree) in the middle. It was beautiful when I got it, and I found it very valuable for investment and collection. Unfortunately, this thing is an artificial titanium crystal tree: titanium crystal is the most expensive counterfeiter in the crystal, and of course it will not let go of such a good product. In the natural environment, it is entirely possible to grow a tree-like titanium crystal in the crystal, but this kind of goods is rare, so how did my counterfeiters do it? Make a hole under the white crystal and spot it into a plate-shaped titanium crystal with a laser, so that the value of this crystal can soar dozens of times. Usually, some titanium crystal torus will be formed by cutting titanium crystal parts into plates and bonding them with round crystals. How to choose crystal products? ① Look at the raw materials: crystal products with excellent materials should have no glue mouth and cotton wool; Pure, smooth and crystal clear texture, suitable for white crystal. ② Look at workmanship: There are two kinds of crystal products processing techniques, grinding and carving. Such as crystal necklaces, bracelets, earrings, etc. Belonging to abrasive products; Guanyin statue, painted snuff bottle, etc. It belongs to sculpture. ③ Look at polishing: the quality of polishing directly affects the value of crystal products. Polishing is divided into soft polishing and hard polishing. ④ Look at the eye hole: For crystal products (such as necklaces, bracelets and beads), it depends on whether the eye hole is straight, whether the thickness of the hole is uniform and whether there are tiny cracks. The hole wall must be clear and transparent without "white marks" ⑤ Look at the color: even the same crystal has different textures and colors in different parts. Belonging to monochrome, it needs to have uniform chromaticity; If there is a hue on the same crystal, it is required that its hue texture is beautiful and generous. Topaz looks at culture: If the pictogram of inclusions in the crystal can be linked with culture, religion and history, the price will often be several times or even hundreds of times higher than the value of the crystal itself.