钻石级别的辨别（Diamond identification）

钻石级别的辨别（Diamond identification） 钻石级别的辨别(Diamond identification) Diamond grade discrimination The world recognized diamond grading standard was established by the Gemological Institute of America (GIA-Gemmological Institute of America) in 1953. The system makes diamond trading a language throughout the world. The "4C", respectively: Carat Ct (Carat) The unit of weight of a diamond. One carat equals 0.200 grams. One carat equals 100, and 0.30 carat equals 30. In diamond trading, the bare stone transaction is calculated at three decimal places. For example, when calculating a weight "0.388ct", if the price is 12800 RMB per carat, the diamond is priced at 0.388 * 12800 = 4966.40 RMB". On quality jewelry, mark the weight of the diamond at least two decimal places, such as 0.38ct. If you only mark two decimal places, the third will "8", "", "9" to carry, that is, "0.389ct" can be labeled "0.39ct", and a "0.388ct" diamond ring can only be labeled as """. Cleanliness (Clarity or Purity) GIA divides it into: * lack of time (Flawless). Which means it can not have any internal and external defects, including polishing lines. * internal Flawless (Internal). No internal inclusions (No, Inclusions) are allowed, but surface defects (Only, Blemishes) may be allowed. * very small flaws (VVS-Very Very Slightly Inclusion), which is divided into VVS1 & VVS2. Allow a very small flaws (Minute and Inclusions) in the detection of personnel trained with regularity 10 fold magnification is also very difficult to see. * very small flaws (VS-Very Slightly Inclusion), which is divided into VS1 & VS2. Allow a very small flaws (Minor Inclusions), the testing personnel trained with regularity cannot be seen in the 10 fold magnification under. * (SI-Slightly Inclusion), small flaws which are divided into SI1&SI2. Some gem organizations have added SI3. Detection of trained test subjects trained at 10 times the magnifying glass will be easier to see the details. The diamonds are SI clarity with invisible defect (Eye-Clean). * Xiaci (I-Included), including I1, I2 and I3. Detection of trained easily at 10 times the magnifying glass to see details. "I" grade clarity diamonds, also known as the "P" class, come from Yu Fawen (Pigue). In terms of diamond sales worldwide, SI and I1 clean grade diamonds are used for most of the total sales of hand ornaments. According to the GIA standard, is 10 times the magnifying glass observation in the defects of small flaws under the (10x, Magnification). The size and location of defects have great influence on the relationship between the clarity grade and the diamond size is the same size and location of defects in a 0.10ct with a 0.75ct clarity will be two completely different level of cleanliness. Color (Colour) GIA sets the colors of the white diamond in alphabetical order from "D" to "Z"". "D-F" is usually called "colorless" (Colourless); "G-J" is called "near colorless" ("Near Colourless"); "K-M" is "extremely pale" (Faint or Faint Colour). The most common diamond color is from "G-M"". It is difficult to determine the true color after the diamond is finished. The colorimetric method is compared with the Masterstones to simulate the natural light of the diamond under evaluation. According to the evaluation principle of GIA color, color color color stone diamond unknown Bibi is shallow level, Bibi high color stone color than color stone for example, "J" color compared with unknown colored diamonds, if unknown stone is light in color "J" color stone, then this diamond is "I" color. GIA standard color stone is 0.25ct, clarity can not be less than SI2. In recent years the development of high technology (HTHP) to some species (Type II) enhance the low color diamond as "colorless" (D-G colors), the best to choose a famous international laboratory certificate diamond bare stone so in the choice of high color grade diamond. GIA, Laboratories such as HRD and EGL have the ability to test whether or not the diamonds have been processed by the HTHP and are noted in the test report. In addition to the familiar white diamonds, diamonds have many different color diamonds different from white ones, and their grading methods are quite different from those of white diamonds. For example, champagne (Champaign Colour) diamonds are in shades of color from C1 to C7. In addition to common champagne diamonds, nature gives diamonds other colors, Diamonds (Fancy-Coloured), which are rarer and more valuable than regular white diamonds (1 carats of colored diamonds per 25000 carats). GIA according to the rarity of colored diamonds found, they are: red (Red); green (Green); purple (Purple); orange (or golden, Orange & Canary); pink (Pink) and blue (Blue). Deep yellow (Intense, Yellow) and champagne Champaign are more common. Black diamond (Black Diamond) is also a kind of color diamond. The Argyle diamond mine in Australia is famous for producing colored diamonds, especially pink diamonds. Brazil is famous for producing black diamond. Color diamond clarity level is difficult to compare with white diamond, generally in SI and I1 is quite good. The color of diamond identification, GIA will give each diamond color. Conclusion the diamond is rare in the domestic market, the domestic appraisal institutions (according to the national standard requirements of diamond color), the note level, the cause of color marked as "color genesis of late ming". Cut (Cut) The diamond cut is very important for a grain of diamond products. In contrast a perfect diamond cut and cut has a big difference, but also have a great impact on the value of diamonds. A cut from diamond geometric scale evaluation (Proportions), global assessment (Finish) including diamond polishing (Polish) and cut fine degree (Precision). Marcel Tolkowsky is the father of modern diamond cutting, cutting all kinds of special garden today (Round Brilliant Cut) type cutters are developed based on his research on. In January 1, 2006, GIA will launch a new cut standard, this standard is based on GIA over the past 15 years, according to the development model with self testing and computer business and life in different light conditions and the. The new standard will be the diamond cut is divided into five levels: Excellent Very; Good; Good; Fair and Poor. The new cut grading has a very clear and simple criteria like the color of the diamond to the final consumer (DZ) and clarity (IFP3). The new GIA standard cut will bring about a revolution in world diamond industry. The new GIA certificate and the old version of the certificate is very different, adding some elements to distinguish cut. In 2005 October, GIA added some relevant cut rating parameter based on the old version of the certificate, the consumer is connected to the www.diamondcut.gia.edu, and start the software on the home page of "GIA FACETWARE", according to the requirements of Softwear, input the required data, you can get your diamond cut grade (Cut Grading). Round cut standard (Round Brilliant Cut) with 57 or 58 cutting surface, each cutting surface between the geometric symmetry and proportion (Symmetry & Proportion) of diamond products (Fashioned Diamond) has a great influence on the quality and value of. The market has more than 58 cut diamonds, some of them 88 or 158 or even 188 section section, and some companies hold patents on these non-traditional cut. Thanks to computer aided design (CAD) and modern computer-aided diamond cutting design. The multi section (more than 58 slices) is more and more rare diamond resources based on multi section technology can keep the product weight greater (diamond cut diamond, closer to the cone) can make the traditional cut only cut 0.90ct diamond cut out one carat or more, because of the huge price difference between 0.90ct and the new process the carat diamond, diamond dealers get more profits. But from the diamond's perfection, the multiple sections (greater than the 58 cut) do not fundamentally improve the beauty of the finished diamond. In addition, the Japanese company Sumitomo Electric Industries began in 1985 to provide artificial diamond growth to the market, because the growth of artificial diamond has a completely different growth pattern and natural diamond and easily identifiable under the microscope, so the Japanese company with method of multi section will generate artificial lines to minimize.