Lab Reports

Diamond Lab Reports or “Certifications”


A Diamond Certification (most commonly from labs GIA, AGS, IGI, EGL, GSI, and HRD) is a document you receive with most diamonds from an objective 3rd party lab that describes a diamond in all of its characteristics.


Along with each diamond you’re considering, you may receive and review its lab certification. This lab report or certificate will be issued by a grading entity and describes various elements of the diamond, such as carat weight, cut, color, clarity, length and width. Trained professionals evaluate, scrutinize, and measure the diamonds using professional tools, such as a loupe or microscope.


Each entity grades and describes diamonds differently—and sometimes the difference is significant. Several lab entities exist and it’s important to know which ones are trustworthy and reliable, and which ones are not. We, at Roemer Originals, are very selective in which diamonds we bring in to show to our customers. If we do not agree with the grading, we won’t even show it to our customer…”certified” or not.


All of our staff here at Roemer’s are trained GIA diamond experts.  We have two Graduate Gemologists on staff and one Diamond Graduate, all trained to grade diamonds strictly by GIA diamond grading standards and we have all of the lab equipment necessary to grade them accurately in house.  So, if we have a diamond on hand that is not certified, it will be graded by the same strict standards that they will be using in the GIA laboratory.


Because diamond certificates are not created equal, the price and value of diamonds are not comparable across varying certifications. As we show diamonds to our customers, we will point out these differences, not only in quality, but also in cost.  Diamonds, and lab reports, are not created equal.  This is part of the reason why prices can vary so much even when looking at diamonds that all have the same specifications.  There are ranges within the ranges, and there is subjectivity within the industry when it comes to grading.


Consistency comes first


Consistency is just as important as grading. For example, the GIA will not grade a diamond the same way the IGI rates a diamond. The reliability of the Color and Clarity grades—and in some instances the Cut grades—is only as good as the certifying lab’s reputation. But if one lab consistently gives a single Clarity grade higher than another lab, that lab is by no means less “authentic.”


To highlight the importance of this issue, take Color grades as an example. We recommend sticking with an H color or better when putting a diamond in a white gold or platinum setting.  You may think you have found a steal with an H color diamond with an IGI certificate. But once you have it home, you realize the diamond has a yellow tint. This is because the diamond is really an I color—by GIA standards—and the IGI just offers a weak certificate.

Rather than simply comparing grades between certifications, look for consistency within the entity’s grading decisions.


Of course, not being in the industry, you may not know what these consistencies are within the labs.  That is when it is good to have the knowledge of a jeweler that you trust to guide you in these buying decisions.  There are labs that are consistently “off” on color and clarity grading.  Let us talk you through these things. When we bring in a selection of diamonds to show you, we can teach you about what we have learned and we will help you choose the best diamond that your money can buy.


Are those less consistent lab graded diamonds priced lower than GIA graded diamonds? Well of course they are! Because they are substandard diamonds compared to their GIA counterparts.


When comparing an EGL G SI1 diamond to a GIA G SI1 diamond, for example, you are typically not comparing apples to apples, and it’s something that we will be able to show even an untrained eye when pointing it out in our store while the two stones are lying next to one another.


This is just one reason why it is so important to shop for diamonds with your own eyes from a selection of stones and never just purchase a stone from a certification online.


Never buy a diamond from just a piece of paper and an image online.  We don’t buy them that way as industry professionals.  We compare them to other diamonds. We look with our eyes. We compare how they sparkle.  Nothing can take the place of that.


GIA Certification


The GIA (Gemological Institute of America) is the most well-respected and renowned diamond grading entity. They are incredibly consistent and provide the greatest peace of mind when purchasing any diamond.


GIA has no financial stake in the sale of the diamond and evaluates diamonds on a variety of qualities and elements, including:

  • Diamond’s evaluation date
  • Measurements (in millimeters)
  • Cutting style and diamond shape
  • Carat weight
  • Table %
  • Depth %
  • Culet size
  • Symmetry
  • Proportion diagram
  • Polish grade
  • Girdle thickness
  • Cut grade (Excellent, Very Good, Good, Poor)
  • Color grade (ranging from D to J)
  • Clarity grade (IF, VVS1, VVS2, VS1, VS2, SI1, SI2)
  • Diamond plot showing all blemishes and inclusions
  • Fluorescence grade
  • Laser inscription (if applicable)
  • Security features
  • General comments

GIA has a reputation for rating Color and Clarity, the most subjective scales, more rigorously. Because of GIA’s high reputation, proven consistency and history, we recommend buying diamonds with a GIA certificate. AGS certificates come in as a close second in their strict grading standards.


As far as the other labs, while we at Roemer Originals won’t completely reject diamonds that have been graded by other laboratories, we will double check their standards and will be honest with our suppliers as we accept stones to show, and with our customers as we show those stones, as far as what we feel are the best stones and certainly the best values for how they are graded.


We were trained by the best and we want only the best for our customers.