Is there something fishy about jade identification? How to Identify Ming and Qing Dynasty Jadeite

We know that the application of jade began in the late Yuan Dynasty and early Ming Dynasty, and it was not until the middle and late Qing Dynasty that it was widely used, especially among the powerful and wealthy classes. As a result, a large number of jadeite from the Ming and Qing Dynasties (mainly the middle and late Qing Dynasty and the Republic of China period) have been passed down to the present day and often appear in the market.

Since the age is relatively close to us, and jade products in the late Qing Dynasty and the Republic of China were no longer monopolized by the ruling class as in the Shang and Zhou dynasties, but were widely used among the people, the carving themes and shapes were more in line with folk customs and were similar to today, so the characteristics of the times alone can only be used as a reference for identification. We can only distinguish them from the traces of processing technology, but it is difficult to clearly determine whether a jade product is from the Qing Dynasty or the Republic of China, or whether it was seen before or after.

Therefore, I personally believe that the focus of the value assessment of a jade product is still on its own quality rather than whether it is new or old. Whether it is natural is a prerequisite. However, there are often doubts in the market about whether jade is natural or not, especially jade from the Ming and Qing dynasties.

Often, a jade product that has been handed down from generation to generation or clearly unearthed will show the result of B-grade or C-grade when identified by scientific instruments in some jewelry appraisal centers, leaving collectors puzzled. Some counterfeiters also take the opportunity to exploit this loophole and make wild claims: jade from the Ming and Qing dynasties will behave like this when identified by instruments, thereby allowing their contemporary acid-washed and glue-injected counterfeits to slip through and defraud money.

To solve this doubt, we must first understand two issues. One is the principle of using instruments to identify whether jade is natural, and the other is the jade processing technology and process in the Ming and Qing Dynasties.

Nowadays, the large instruments in jewelry appraisal laboratories are basically infrared spectrometers. Infrared spectra are also called molecular vibration and rotation spectra. When the sample is irradiated with infrared light of continuously changing frequency, the molecules absorb some of the radiation at some frequencies, and the vibration and rotation energy levels transition from the ground state to the excited state. The transmitted light in these areas is weakened. The curve that records these changes is the infrared spectrum. Different substances have different infrared spectra. Although the matrix of natural jade and processed jade is the same, the spectra also change differently due to the invasion of foreign substances (glue, wax, etc.). Simply put, a jade product with glue or wax peaks can basically be identified as B or C goods.

The absorption peak of organic gum is around 3036cm-1 to 3058cm-1, and the absorption peak of wax is around 2920cm-1, 2850cm-1. The concave part of the transmission spectrum is considered absorption. The red spectrum has no concave at the above position, which is a natural jade spectrum; the blue spectrum has concave at 2920cm-1 and 2850cm-1, which is a small amount of wax-filled jade; the orange and green spectra have concave at 3036cm-1, 3058cm-1 and 2920cm-1, 2850cm-1, which are bleached and filled jade (B goods)

However, some natural jade products, especially jade from the Ming and Qing dynasties, are often detected to contain glue or wax. Let us first briefly understand the processing procedures of some traditional jade products.

An object made from a piece of jade that is carved through specific craftsmanship and processes is called a jade artifact, and the processing of jadeite is no exception. The first step is to identify the jade, peel it, cut it, design it, carve it, polish it, wax it, etc.

Waxing is an important step in jade processing. Some information left in the Beijing Jade Factory shows that jade, especially jadeite, has another step before waxing, which is "waxing with sour plums". That is, boiling water with dried sour plums or soaking the shaped jade in acetic acid to clean it. This soaking process lasts about three to five days or even longer. The purpose is to remove some impurities on the surface of the jade through weak acid, and then boil the wax. This process is actually similar to the processing of current jadeite BC goods.

Therefore, jadeite from the Ming and Qing dynasties is often detected to contain wax or other substances, but after all, it is a weak acid and will not corrode the entire piece, so its natural internal structure is not destroyed. This is also an important aspect in our identification of whether it is natural.

fcgc66

fcpf18