Which Diamond Certificate is Best?
Diamond certificates have really leveled the playing field for today's informed Diamond shopper. But hey reading a Diamond Report or "Cert" is really , really boring stuff ! Most shoppers won't take the time to learn about "table percentage" or "crown angle" and who could blame them,, it's stuff even most jewelers won't read much less understand!
Today's Diamond shopper need to grasp but a few Certificate basics to ensure complete success at the Diamond counter (virtual or material). Here are some simple rules you should know,,, Hey if this is too much to read jump to the bottom of the page to get the condensed version.
- Not all Diamond certificates /reports are equal ! Don't be fooled into believing that an "IGI" cert carries the same weight or value as either "GIA" or "AGS" reports ! If you are doing any comparison shopping make sure it is an apples to apples comparison. What certs do jewelers use most for accurate grading? Hands down it is "AGS" or "GIA" they have the reputation of being very "strict" graders and as a result jewelers base the true value of the Diamond with these two certs. Jewelers also use "EGL" certs but these stones are bought with a "discount off "the "GIA/AGS" cert price, and that discount is usually 10-20%.
- Beware the "house cert"!! These are usually nothing more than the sellers opinion of the Diamonds grade. These are usually generated by trade friendly labs to help jewelers sell sub standard diamonds. Many Certs/Reports use initials and names in an effort to sound like or imitate the big boys, for example GIS , GLS and GAL to name a few. Many of these certs are fairly well printed and usually laminated, many with embossed imprints or gold seals to make them look official. Some jewelers actually offer their appraisal instead of a certificate, don't fall for it.
- Jewelers that use these certs may be engaged in "Grade Bumping". The FTC (federal trade commission) requires that a Diamond be within one clarity grade and one color grade of what the Diamond was "sold as". For example if a jeweler buys a SI1(G) he'll bump it with a house cert and sell it as VS2(F), the dealer is legally covered and puts considerable extra cash in his pocket! , You lose !
- Don't let jewelers confuse you with "cert talk" like table percentage, total depth and crown angle. In regards to Diamond cut grades the math has already been done, you can analyze all you want but the bottom line is that if the Cert is reputable like "GIA/AGS" then you can trust their report or findings on cut or finish. For "GIA" ,Polish and Symmetry are the criteria graded and both are described as Excellent, Very Good, Good, Fair and Poor. So for example a diamond with very good polish and good symmetry , would be described as "VG/G". If you stay with diamonds graded as EX/EX or VG/VG or any combination of the two you can be assured the diamond is very well "made". As for "AGS" the approach is a bit more quantitative. AGS employs an 11 point grading scale with "0" as the best and "10" the worst. They measure Proportion, Polish and Symmetry. For example a stone graded "000" is considered Ideal. If you select a Diamond in the grade range of "0 thru 2" , you will be assured the diamond your considering is very well cut and polished. If you check out online jewelers like Blue Nile or Mondera you can use their clever Diamond search tools to find diamonds graded by GIA and AGS exsclusively. Both sites by the way are a great place to start your research.
- Take a little time to learn about color and clarity, this is really up to your likes and dislikes. Just know you should consider diamond color grades "J" or better and clarity grades SI2 and better. And consider these 2 lower grades if and only if they are graded by GIA or AGS !
So here are the highlights: Just some more stuff your jeweler probably won't tell you.
- Both GIA and AGS are really the only certs you should consider.
- Avoid at all cost "In House" Certs or Jewelers Appraisal in lieu of a certificate.
- Beware of low end Certs that foster "Grade Bumping".
- Consider only GIA cut grades excellent and Very Good and AGS "0-2"
- Consider only J-SI2 or better, and only consider J-SI2 stones if they are GIA or AGS graded.





