First of all, diamond is one of the hardest stones known, so we can know it simply by carving corundum with diamond. Oiliness test: Use a special pen or ballpoint pen dipped in oily ink to draw a line on the diamond table, leaving an uninterrupted straight line. While other copies are not lipophilic, leaving intermittent dotted lines at the scribe line. Water drop test: the water drops on the diamond will remain spherical for a long time, while the water drops on the copy will disperse in a relatively short time. Breathing test: breathe into the diamond, if the water vapor on the diamond disappears immediately, it becomes a real diamond; If the water vapor stays on the diamond for a few seconds before it disappears, it is a fake diamond. I think the test: when you touch the diamond and its replica with your tongue at room temperature, the diamond is much cooler than the replica. A very simple and good way to judge is to put it on a piece of wired paper and put it upside down to see if you can see the line through it. If it can be copied, natural diamonds can't be seen. This method is very simple. However, my personal suggestion is to use "diamond pen (also called thermal conductivity meter)" to distinguish. This is simpler and more scientific. The production method of crystal and stone crystal is that crystal has "crystal nucleus (a kind of flaky longitudinal inclusion)", but stone crystal does not. In addition, the uniform color of crystals and monotonous types of inclusions are also a way to distinguish them from rock crystals. (1) At first glance, due to the influence of the environment, crystals are always rich in some impurities. When you look at the sun, you can see a weak consistency. Fake crystals are mostly made of inferior crystal slag and glass slag, which have been melted, polished and colored from beginning to end, without uniform stripes and catkin-like substances. (2) Tongue licking: Even in the dog days of hot summer, licking the surface of the crystal stone with your tongue will feel cold and cool. Fake crystals are not cool. (3) Illumination: The crystal stone stands upright in the sun, and it can shine beautiful colors from any angle. Fake crystals can't. (4) Hardness: The hardness of the crystal is very high, and it is cut off quietly on the jewelry with gravel without leaving any traces; If there are streaks, it is a fake crystal. (5) Inspection with a polarizer: the rock crystal changes its brightness at 360 degrees under the polarizer, while the fake crystal remains unchanged. (6) Check with dichroism: natural amethyst has dichroism, while fake amethyst has no dichroism. (7) Magnifier inspection: under the transmitted light, the bubbles that can be found can be basically classified as pseudocrystals. (8) Check with hair: If the crystal is placed on a hair and the human eye can see the double shadow of the hair through the crystal, it is a rock crystal, mainly because the crystal has birefringence. (9) Test with thermal conductivity meter: When the thermal conductivity meter is set to green 4 to test the gem, the rock crystal can rise to yellow 2, the false crystal does not rise, and it rises to yellow 1 lattice when the area is large. A simple way to distinguish diamonds is that with the increasing demand for jewelry diamonds in society, fake diamonds such as artificial diamonds are constantly flooding and expanding shopping malls, and even some jewelry operators can't distinguish them. Here are some simple ways to tell the truth about diamonds. 1, the single refraction of diamond is determined by the essential characteristics of diamond. Other natural gemstones or artificial products are mostly birefringent. When using 10 times magnifying glass to query fake diamonds, it is easy to see the superimposed image of the spearhead line and two bottom lights from the slightly inclined front. If the birefringence is unusually small, such as zircon, you can also see the image of the bottom light pile. 2, the adsorption of diamonds Diamonds have a positive affinity for oil and dirt, which means that oil is only adsorbed by diamonds. So touching the diamond with your fingers will feel sticky, and your fingers will feel sticky. This is not found in any gem. This method needs practice to master the wonderful difference. 3. The surface of the diamond with straight features is polished smoothly. Dip the pen in ink and cross the diamond. If it is a real diamond, the surface will leave a smooth and continuous line, which is characterized by a straight line. Forgery will leave dots and lines. In this way, the query depends on a magnifying glass. 4. The unique diamond luster is roughly under the incandescent light of 100 degree. Compared with the fake, it is easy to see which diamond has diamond luster. This method should not be carried out in too dark or too strong light.