Pitfalls and counterfeiting of ancient jade ①: Comparative evidence of ancient jade in pits and counterfeits

The pits and counterfeiting of ancient jade ①: Comparative evidence between Shengkeng ancient jade and fakes The so-called Shengkeng ancient jade refers to ancient jade that has not undergone any cleaning treatment after being unearthed. It maintains the original state of the ancient jade when it was unearthed. After being buried underground for hundreds or thousands of years, this kind of pit jade will have sticky soil and other complex accompanying substances on its surface, and it will have very strong adhesion.
Evidence 1: After the raw pit jade has been cleaned, whether it is oxidized rust spots or sedimentary soil attached to the surface of the jade, after it falls off, it will leave traces of oxides or soil on the surface of the jade, and some are along the surface. Some of the cracks in the jade penetrate deep into the surface of the jade. Whether it is the oxidized rust on the surface or the soil attached to the jade surface, these deposits are very dense and extremely fine.
When counterfeiters forge this pitting effect, they mostly use adhesives mixed with soil or rust powder for gluing. The forged soil or iron oxide and other substances are extremely rough and have low density. Because it is artificially bonded, after the surface camouflage is cleaned or peeled off, there will be no traces of penetration on the surface of the jade, and its bright texture is no different from other parts.
Evidence 2: Due to the uneven hardness and uneven corrosion resistance of the jade material itself, the long-term fumigation of real ancient jade at underground temperatures and the long-term erosion of various contact substances will cause the petrification of jade. This kind of dehydrated and petrified jade or completely petrified jade will have different degrees of delamination on the edges, edges, corners and other parts that are easier to touch. When the petrified skin falls off, the powdered structure is exposed under the skin. .
The counterfeiters’ counterfeits, whether they use high-temperature sintering or chemical etching, can produce a white petrified effect on the surface of the jade, but the weight of the jade itself will not change. Counterfeiters use this enhanced treatment method to make the surface of the jade appear opaque and petrified, but its surface still shows a hard stone structure. As long as we observe carefully, we can find the difference between the fake and the genuine article.
Evidence 3: After long-term underground corrosion of ancient jade articles in Shengkeng, some parts of the jade articles will be naturally damaged. Some of these damages will gradually become less hard after corrosion, resulting in angular and angular defects. After complex burial changes in the ground, the jade has been damaged. After hundreds or even thousands of years of oxidation and aging, when the ancient jade is unearthed, we will find that its damaged edges and corners will have natural ridge and trace transitions. Under normal circumstances, some complex substances will be deposited on the damaged parts of authentic ancient jade, which are difficult to remove.
Fake products have not experienced long-term underground burial and corrosion evolution. In order to make the fake products more realistic, counterfeiters use artificial impact to deliberately create fake damaged structures. However, it can be found from the damaged parts that the damage of the jade does not show the evolution process after corrosion, and the forged damaged parts will produce new residual marks. In addition, in order to further disguise some fakes, they use fake colors to cover up artificial traces. In fact, the color of the deposited pigment of this fake Qin color is very different from the Qin color of the authentic ancient jade, which instead exposes the flaws of the fraud.
Evidence 4: A white alkaline film will appear in the dead corners of some raw pit jade articles. Due to the special location, this white film can be retained for a long time and is still difficult to remove after repeated cleaning. The penetration of this white alkaline substance, after microscopic observation, appears to be quite delicate and has penetrated deep into the jade. Usually, there are corrosion pits on the surface of raw pit ancient jade to varying degrees. According to the traditional explanation, these pits are insect bites and insect infestations. This view is wrong. And it has no scientific basis. From a biological point of view, no microorganism can bite the high-hardness jade material. After long-term practical inspection and research analysis, the author believes that the root cause of this phenomenon is mainly caused by the material properties of the jade material itself. We know that jade itself contains many impurities. If these particles are exposed on the surface of the jade, they will be easily oxidized and volatilized after long-term burial and corrosion, causing pits to form on the surface of the jade.
Counterfeiters forge the pit features and white alkaline film, mostly using corrosion methods. This method mainly uses a weak acid corrosive to slowly corrode. On the one hand, it strictly controls the corrosion degree, and on the other hand, it quickly oxidizes and removes some impurity particles to form aging pits. Another method is to use an alkaline corrosive for enhanced etching. This enhanced etching will also produce a white film. However, this alkaline film is structurally different from the genuine product and will produce a certain degree of corrosion layer, showing There is no obvious penetration phenomenon on the surface of ancient jade.
Evidence 6: There are cracks caused by the material itself in some parts of Shengkeng jade. After long-term underground corrosion, these cracks will gradually reduce the hardness of certain parts, resulting in natural damage and attenuation, thus causing the cracks to It is easy to cause black or red ecstasy. Under normal circumstances, once the jade material breaks or cracks occur, or the surface of the petrified jade gradually loses its brightness and delaminates, the performance of the jade and the clarity of the craftsmanship will be affected to varying degrees. In addition, some ancient jade from raw pits will produce special scale phenomena after long-term underground corrosion. Such oblique scales will also produce varying degrees of exposure.
After counterfeiters use new materials with cracks to process the counterfeit products, they usually perform artificial dyeing again. This kind of counterfeit products is manifested in that the cracks of the new material have no long-term aging effect and transparency, and the cracks show It has a sharp tooth-shaped fracture structure. If the counterfeiter performs color camouflage, the sticky additives in the pigment will adhere to the cracks. If the counterfeit has some material defects before it is forged, then the knife jump phenomenon will inevitably occur during the grinding and processing process. As long as people with common sense of mechanical technology can easily understand this truth. At present, all counterfeit ancient jades lack the long-term underground burial and erosion evolution process, so it is impossible for them to have the natural decay, cracking and petrification phenomena of authentic ancient jades.
Article editor: Xinchangyin Art Appraisal Database (public account zh) aims to provide everyone with high-quality art collection and appraisal knowledge, updated every day.