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What is the difference between diamond GIA and GMA certificates?

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1. Institute America? : Logo of GIA laboratory

2. GIA DIAMOND DOSSIER? : Certificate name

3. March 7 2005: date of certificate issuance. This date also represents the detection level and dollar price at that time. But now we settle accounts in US dollars on the purchase date, so we don’t investigate this date

II. The first part of the certificate

1 Laser registry: laser marking “laser number”. The laser number engraved on the diamond waist of GIA 13945200 is black. The three words of GIA are hollow letters, and the number is consistent with the number of report, which is used as a proof of the identity of GIA diamond

2. Shape and cutting style: diamond cut. Round is a round drill. For knowledge, please refer to standard round drill bright cutting. Diamonds of other shapes have their unique names, such as emerald cut

3.: Diamond size. 4.44 – 4.48 x 2.76 mm, diameter (min max) * height diameter is allowed to be a range, in millimeters

III. certificate content Part II – 4C

1 Carat weight: diamond weight. 0.33 carat。 Carat is the weight unit of diamond, which is called “carat” in Chinese. 1 gram = 5 carats, 1 carat = 100 points. GIA is calculated to 2 digits after the decimal point, and the third digit is one every 9. For example, 32.89 is 32 points and 32.9 is 33 points

2. Color grade: diamond color. G is the color of this diamond. Gem grade white diamond starts from D color to Z color. For knowledge, you can refer to color. In addition, colors such as pink are called colored diamonds, such as Fancy Pink. There are also many levels of color diamonds, which will be introduced in detail in future articles

3. Clarity grade: Diamond clarity. VVS2 is the cleanliness of this drill. That is, the content of diamond under 10x magnifying glass. GIA divides the diamond clarity into FL, if, vvs1-vvs2, vs1-vs2, si1-si2-si3, i1-i2-i3 and other levels, which are reduced from front to back. Generally, we think the high cost performance of wearing is vs1-vs2, and the collection is if. If it is worn and played, then Si is also OK. However, we suggest buying domestic certificates for Si, which costs a lot less; Knowledge can refer to clarity

4. Cut grade: diamond cutter. This is a comprehensive evaluation of the new addition. It depends on the cutting of 4C! In fact, it is a comprehensive measurement of many indicators, including symmetry and polishing. Excellent is our drilling and cutting worker. Knowledge can refer to cutting

IV. certificate content Part III – additional information

1 Clarity: inclusion. The internal characteristics of some natural diamonds, such as crystal small crystals and cloud cloud inclusions, can be found under the microscope to prove the naturalness of diamonds

2. Finish: finish degree. That is, the modification of the beauty of the diamond after the diamond cutting is completed. A little more life-oriented is the type of makeup and hairstyle, which is not as important as the main body such as cut cutting. However, if the modification is better, it will also increase the beauty of the diamond. The degree of modification is divided into two aspects:
A, Polish: polishing. Polishing will increase the brightness of the diamond. However, some diamonds have natural characteristics, such as the original crystal surface, which cannot be polished off. So if this is the natural situation, don’t be too demanding on polishing
B. symmetry: symmetry. Symmetry is whether a diamond is cut symmetrically, because all diamonds have the largest and smallest diameters, and no diamond is completely symmetrical. If the symmetry is above good, there may be eight heart and eight arrow effect, but it does not mean that eight heart and eight arrow is a good cut. Remember that it is only a special effect

3.: Fluorescence. It is a natural phenomenon that diamonds have fluorescence. The blue fluorescence can enhance the brightness and whiteness of diamonds, and the yellow fluorescence can be reduced. Therefore, the fluorescent diamond also depends on which kind of light. It doesn’t matter if there is fluorescence, which may make the diamond more beautiful. For knowledge, refer to the description of fluorescence in color

v. Part IV of the certificate content – cutting logo

the information on the right side of the certificate. Ordinary consumers only need to look at the cut grade evaluated by GIA. In fact, GIA has summarized these complex data into a comprehensive cutting evaluation
1. Full depth ratio: the percentage of diamond height and relative waist average diameter. This ratio depends on the cutting. GIA’s standard is 56.8-62.4%, which is good-excel

2. Table width ratio: the percentage of the table width relative to the average diameter. The table size is related to the size of the diamond and whether it will leak light. GIA’s standard is 52.5% – 58.4% for Excel. Americans prefer small countertops, which will make the fire color of diamonds very sufficient. So some people say that the bigger you buy, the bigger it looks. It does look big, but the diamond leaks light and has no fire color. It’s meaningless to be big

3. Diamond waist thickness: if the waist is too thin, it is easy to damage the broken edge. If the waist is too thick, it will increase the weight

4. Bottom tip: none. Generally speaking, the bottom tips of small diamonds are reserved. In order to protect the bottom tips of diamonds from damage, some large diamonds grind off the bottom tips in advance and have an extra face

in addition to the diamond color and clarity classification table, bar codes and laser squares are fake

[this post was last edited by Sarah at 22:30 on April 10, 2008]

the bare drilling certificate of GIA international is one of the most authoritative certificates now. GMA is not very good

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