Diamond Certification

Before you purchase a diamond, you must ask to see the certification. Preferably, the certificate will be issued by the Gemological Institute of America, or the GIA. The GIA provides a service to consumers, ensuring that the diamond that they are purchasing is indeed everything that the seller claims that it is.

Most independent laboratories that certify diamonds do so based on the GIA’s guidelines. This includes the American Gem Society (AGS). In Europe, the European Gemological Laboratory (EGL) issues certificates for diamonds. Getting a certificate for a diamond can cost anywhere from $100 to $200. But in the end, this is money well spent.

Ironically, the GIA does not call diamond certificates ‘diamond certificates.’ They call them Diamond Grading Reports. This is because they are not actually certifying anything, because they have no idea what the seller is telling you. They simply examine the diamond, and issue a grading report for it. The GIA just wants to be clear that they are not endorsing a diamond.

A diamond grading report is issued by the lab. It actually is a certification that the diamond has been examined by a gemologist, and at the time of the examination, the diamond was everything that is in the report. Gemologists use special tools that allow them to see what the naked eye – or the non-professional – cannot see. The things that they can see have a huge impact on the price of the diamond.

If a jeweler does not already have a diamond grading report for the diamond that you are considering, you should ask him or her to send it to the GIA for examination. If they don’t wish to do that, it’s time to find a new jeweler – it means that they’ve probably told you something that isn’t true. Reputable jewelers don’t have a problem with this at all.

When a report is made, each diamond is given a unique reporting number. This number appears on the certificate, and is just a way to identify the diamond at the lab. If the jeweler has a certificate already, get that number and call the lab to verify it. At the GIA, that number is micro lasered into the diamond. This does not alter the diamond however.

The next thing on the report is the shape and cutting style. The shape will be either round, pear, heart, square, or oval. The cutting style refers to the cut of the facets, and includes brilliant, marquise, emerald, princess, step, or mixed. This is followed by a measurement of the diamond. The measurement is done by diameter x depth or length x width x depth, depending on the shape of the diamond. The diamond is also weighed to get the carat weight. It is then rounded to the nearest hundredth of a carat.

Following measurements, the report focuses on the color grade of the diamond. On GIA reports, this is indicated by a letter. The best color grade is D, and the worst is Z. Fancy colors are also determined on the report.

The next item of importance on the report is the clarity rating. Clarity is rated from F (flawless) to I3. We discussed the meaning of these ratings earlier. Clarity is determined with the aid of a stereo microscope, so every potential flaw is seen. However, the diamond grade that appears on the report is that which was determined with the use of a 10X microscope.

A new addition to the GIA report is the Cut Grade. It is stated as excellent, good, fair, or poor. The polish and symmetry of the diamond are also stated as excellent, good, fair, or poor. This is an indication as to how even the facets of the diamond are, and how symmetrical they are. Polish refers to the polish on the facets.

If the diamond is Fluorescent, this will be stated on the report as well. If a diamond is fluorescent, it will have a long wave of ultraviolet radiation. For example, if light shines through a fluorescent diamond, a rainbow of colors will result on the other end. Fluorescence is stated as none, very faint, faint, faint blue, medium blue, strong blue, and very strong blue. Very strong blue is the best rating here.

There will also be comments made by the gemologist on the report. These comments are made to give information about the diamond that cannot be covered elsewhere on the report. The report will also contain a drawing of the diamond, so that you can see where all of the facets are. This is done to further ensure the integrity of the report, so that the report can be associated with the diamond for verification purposes. In this drawing, or plot as it is called, characteristics of the diamond are labeled.

If you aren’t sure that a certificate supplied by the jeweler is the certificate for the diamond in question, have a jewelry appraiser – one that does not sell diamonds – verify it for you. Again, you want an appraiser that does not deal in diamonds to get a fair and impartial opinion.

Finally, note that a certificate is not an appraisal. The report/certificate will not state the monetary value of the diamond. You need an appraiser for that. We will discuss finding and working with appraisers later. Furthermore, you need to look closely at the report, to ensure that it was compiled by the GIA Lab and not by a student at GIA’s school for Gemologist.