Identification and color grading of natural pink diamonds
Natural powder drills have long been rare due to their production, and the beauty of “long look†has been regarded as a treasure by collectors.
For a long time, there have not been enough pink diamonds anywhere in the world to meet the needs of extensive and in-depth research. In the past 20 years, pink diamonds have been mined and processed due to the mining of the Argyle mine in Australia, but the number is still limited.
Now the GIA TradeLaboratory of GIA in the United States has the results of the identification of 1,500 pink diamonds and related data. The characteristics and color grading system of natural pink diamonds were determined through research.
Pink diamonds include: pink-pink-orange-yellow pink in light purple tones. Among them, the color classification of American GIA pink diamonds is: faint pink (Faint), very light pink, light pink, fancy light, normal pink (fancy), deeper Pink (facyintense), deep pink (fancyDeep), bright pink (fancyvivid).
The reason for the coloration of colored diamonds remains to be studied. Some studies have suggested that it is caused by defects in diamond crystals, which is consistent with the cause of browning of brown diamonds. The study also pointed out that pink diamonds include Type I and Type II. Among the 1490 pink diamonds tested, 1166 pink diamonds type I and 324 pink diamonds type II, which means that the proportion of pink diamonds in type I diamonds is large, while the proportion of pink diamonds in type II diamonds is small. However, the study also found that the type II pink diamonds are mostly heavy, while the type I pink diamonds are mostly small, which means that the pink color of the diamond is not only related to the type of diamond, but also related to the weight. The rate of change of pink in different types of pink diamonds is also different.
The identification of pink diamonds, the clarity of which is almost irrelevant, is completely different from the requirement to identify and evaluate colorless diamonds. However, the results of the pink diamond identification confirmed that 68% of the type II pink diamonds were above VS, and all the samples tested, the pink diamonds with VS clarity accounted for only 51%.
Pink diamonds are illuminated by purple light (whether long or short), and most have little or no fluorescence effect, but the color can change during the cutting process.
The pink diamond study found that nearly 1/2 of the pink diamonds studied showed a ribbon display, with a ribbon of type I pink diamond showing no more than 65%, and only 12% of type II pink diamonds having a ribbon.
After treatment is a technical treatment method that gives the fabric a color effect, a morphological effect (smooth, suede, stiff, etc.) and a functional effect (watertight, non-ironing, non-sticking, flame resistant, etc.). The process of improving the appearance and feel of the fabric by chemical or physical main methods, improving the wearing performance or imparting special functions is the processing process of textiles.
The after treatment method can be divided into two categories: physical/mechanical finishing and chemical finishing. According to the purpose of finishing and the different effects, it can be divided into basic finishing, appearance finishing and functional finishing.
Our after treatment products are mainly calendered, embossed and pearl paste printed fabrics.
The purpose of finishing:
1. The textile width is uniform, and the size and shape are stable. Such as heat setting.
2. Enhance the appearance of textiles: including increasing the gloss and whiteness of textiles, and enhancing or reducing the surface fluff of textiles. Such as heat setting, crinked/ creped, bubbled, mercerized.
3. Improve the feel of textiles: Chemical or mechanical methods are used to give textiles a comprehensive touch feel such as softness, smoothness, fullness, stiffness, lightness or thickness. Such as soft, stiff, weight gain and so on.
4. Improve the durability of textiles: mainly use chemical methods to prevent damage or erosion of fibers caused by sunlight, atmosphere or microorganisms, and prolong the service life of textiles. Such as anti-mite, anti-mildew finishing.
Give textiles special properties: including some protective properties or other special functions. Such as flame retardant, antibacterial, water repellent, oil repellent, anti-UV and antistatic.
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