Real gems or "fake gems"? Talk about "gemstone improvement"...

Gem lovers all hope to buy a genuine, authentic and genuine product, but sometimes the treasures they buy at a high price will soon fade, change color, crack, cracks, and poor transparency, which makes people very upset and call the merchants bad. In fact, high-end pure natural jewelry is rare. Many gems have been artificially modified when they are placed on the shelves. Of course, the purpose of these modifications is to increase the beauty and durability of the gems, but the craftsmanship and processing quality directly affect the quality of the gems, so you should be very careful when buying precious gems.

diamond

Artificial modification of natural gemstones is collectively referred to as "gemstone improvement", which is to use artificial physical and chemical methods to change the properties of gemstones, including color, clarity, density, etc., to improve the beauty and durability of gemstones. The improvement effect must be stable, harmless to the human body, and non-polluting to the environment. Gemstone improvement can be divided into two categories: gemstone optimization and gemstone treatment.

Emerald

Gemstone optimization: After heat treatment, immersion in colorless oil, immersion in wax, bleaching and other processes, the appearance of natural gemstones is stably and lastingly improved, and no foreign substances are added to the gemstones or foreign substances have been accepted by tradition. For example, the dyeing of agate and chalcedony can also be regarded as optimization.

Gemstone optimization improves the quality of gemstones and is long-lasting and harmless. For example, the black blue sapphires produced in Shandong, my country, are dark in color and poor in transparency. After being heated at more than 1200℃ in an oxidizing environment, they can be transformed into colorful blue sapphires; low- and medium-grade emeralds can be injected with cedar oil or Canada gum with similar refractive index to make up for the defects caused by cracks and upgrade the grade of gemstones.

According to China's national standards for gemstones, when gemstones that have been optimized are put on the market, there is no need to explain the processing technology, and the name of the original gemstone can be used directly.

Emerald before and after oiling, the flaws have basically disappeared

Gemstone treatment: Gemstones undergo certain technological transformations, their appearance is improved, and their appearance becomes more beautiful, but the effect of this improvement is not stable and lasting, or foreign substances are added. Such as radiation, filling, dyeing, coating or laminating, filling or filling after bleaching, impregnation with colored oil or colored wax, surface diffusion treatment and laser drilling to remove defects, etc.

Dyed Jadeite - C Grade

Gemstone treatment is not fake, but although the treated gemstones look gorgeous, their value should be greatly discounted. Take dyeing treatment as an example. People use copper sulfate, potassium iodide, potassium ferrocyanide, potassium ferrocyanide, cobalt salts and other chemical reagents to dye jade, crystal, coral, white marble into green, red, blue, and even use silver nitrate to dye white pearls into rare and noble black pearls. But even the famous Japanese nuclear akoya black pearls, if dyed, their color will gradually fade. In this way, the value of dyed black pearls is much worse than that of natural black pearls.

Dyed Pearls

In any case, it is difficult for ordinary gem lovers to accurately judge the quality of gems. Although long-term attention and contact can give us experience accumulation, we must lose some confidence when purchasing precious gems, because even professionals need the help of special instruments to judge the variety, quality and processing of gems, such as microscopes, refractometers, polarizers, dichroic mirrors, spectrometers, color filters, fluorescent lamps, thermal conductivity meters, X-ray machines, etc. Remember, there are risks in purchasing gems, so you must be cautious.

Author: Biological Evolution and Geohistory Team of the Geological Society of China