Since ancient times, Hetian jade has been the darling of the jewelry and jade industry and is deeply loved by people. In addition, Hotan jade has a long history and can be seen everywhere in the jewelry and jade market. More and more people love Hetian Yu. Stimulated by economic interests, some profit-seeking counterfeiters began to optimize Hetian Yu, with mixed true and false, and mixed fish eyes. Today, I will explain the optimization and identification problems of Hetian Yu.
First of all, according to the national standard GB/T16552-2017 "Jewelry and Jade Name", the optimization processing concept refers to all methods used to improve the appearance, durability or usability of jewelry and jade, such as color, clarity, transparency, gloss or special optical effects. , which is divided into optimization and treatment-optimization: a traditional and widely accepted optimization method that can show the potential beauty of jewelry and jade; an unconventional and not widely accepted optimal treatment method.
The optimization treatment method and identification of Hetian jade mainly include the following aspects:
1. Optimization of Hetian Yu;
1. Soaked wax - high-quality Hetian jade, delicate and warm to the hand. To achieve this effect, unscrupulous merchants soak dry, loose, and defective Hetian jade in liquid paraffin wax. After a period of time, paraffin wax will pass through the gaps in the jade, and the originally worthless Hetian jade will "transform" into high-quality Hetian jade, full of oil and full of oil, while covering up defects. Identification methods: (1) there is obvious blue-white fluorescence under ultraviolet lamp illumination; 2, there will be sweating when approaching with a hot needle, and the wax will flow out when it melts by heat; (3) soak hetian jade with hot water. After a while, it will be clear whether it is soaked in wax or not.
2. Oil immersion - Among all the materials of Hetian Jade, the oil of the seed material is the best, and the oil luster is also the strongest. Oiliness is an aspect of considering the quality of Hetian jade, and merchants often coat a layer of oil on some surface defects of Hetian jade, which can effectively cover the surface of fine cracks, micropores, scratches and other defects. Hetian jade has been soaked in oil, which will look beautiful in a short time, but after wearing it for a long time, you will identify it: (1) after being quickly touched, the hands are stained with oil; 2 Wipe the oil with a paper towel to soak Hetian jade, and there will be obvious oil stains on the paper towel; 3 Many oil-soaked jade are packaged in transparent plastic self-sealing bags, so that the oil can dry slowly, so that oil stains can be found on the self-sealing bag;
Second, the treatment of Hetian Yu.
1. Dyeing treatment - improve or change the color, and dye hetian jade in whole or in part. The surface is often dyed brownish red, brownish red to yellow, etc. It is common to grind the scraps into a pebble shape and then dye them to mimic natural materials; or to dye some of the seed material locally, which is called two-color or the reinforcement of the line. Identification methods: (1) amplification inspection, color distribution is uneven, mostly concentrated in cracks, intergranular voids or surface depressions; (2) staining can produce special fluorescence under long-wave and short-wave ultraviolet light; (3) it will fade after wiping with acetone or absolute ethanol; (4) composition analysis instruments (such as XRF) can detect impurities in dyes.
2. Splicing processing: Two or more pieces of Hetian jade hand-spliced Hetian jade jewelry, giving people an overall impression. Identification methods: (1) the obvious seams can be seen in the magnification inspection, and occasionally the bubbles left by the glue can be seen; (2) under the illumination of ultraviolet lamps, the seams can be seen with obvious blue-white fluorescence; (3) the color and texture of the main jade are different from the splicing part.
3. Filling treatment - to improve or change the durability and appearance of Hetian jade. The cracks on the surface of Hetian jade are filled with artificial materials such as glass and resin. At present, there are very few samples on the market filled with Hetian jade. Identification methods: (1) amplification inspection, the surface gloss of the filling part is different from the main jade, and the visible bubbles are filled in the part; (2) the infrared absorption band of the visible filling feature is detected by infrared spectroscopy; (3) the luminescence spectrum analysis (such as ultraviolet fluorescence observer, etc.). The distribution of the filler can be observed; (4) if the filling material is wax, hot needle contact may precipitate wax.
Summary: The wax and oil immersion optimized by Hetian jade is traditionally widely accepted, and there is no need to explain when issuing the Hetian jade identification certificate; but the dyeing, splicing and filling treatment of Hetian jade are not widely accepted, and it should be pointed out when issuing the identification certificate. Xiaobian believes that the optimization processing is not a bad thing, the method is good, but it is used in the wrong place by unscrupulous businessmen, and the defective Hetian Yu is "optimized" and sold at a high price to obtain higher returns.
