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A diamond grading report or certificate is an independent quality report about a specific diamond. It is issued by a diamond grading laboratory with no affiliation to any retailer, giving the consumer a completely objective opinion on the diamond’s quality. This document includes the exact measurements, proportions, color grade, clarity grade, cut grade and carat weight of the diamond. It also includes specifics that most jewelers do not have the equipment or knowledge to determine such as the diamond's fluorescence, polish, and symmetry*. Each document is numbered, dated, and illustrates the internal and external characteristics of the diamond, otherwise known as a 'plot'.

It is important to note that there is no governing body responsible for the standardization of a diamond report. Each company has the latitude to judge to the standards which they feel are appropriate. For this reason, many laboratories fall in/out of favor depending on how it is being operated. It is also important to know that every grade received has an allowance for deviation. For example, a diamond that has been graded excellent for proportions, polish, and symmetry does not mean that it is 'perfect'. Rather, it refers to the fact that all of those qualities fall under a pre­determined standard, which has allowances for error.


The leading diamond laboratories in the world are the Gemological Institute of America (G.I.A.), The American Gem Society (AGS), Forevermark Diamond Institute, and the European Gemological Laboratory (E.G.L.). Any diamond can be evaluated by G.I.A, A.G.S, or E.G.L. for a fee. The Forevermark Diamond Institute tracks the diamond’s source and therefore will not accept diamonds from outside its own supply chain

  • GIA (The Gemological Institute of America) ­ established in 1931 and is recognized as the world’s foremost authority in diamond grading. The G.I.A. grades natural, synthetic and treated diamonds. G.I.A. refers to their document as a Diamond Grading Report or a Diamond Dossier (depending on carat weight).
  • AGS (American Gem Society) was founded in 1996 with a mission to help protect the consumer by establishing stricter guidelines of diamond grading. They were the first laboratory to establish the ideal cut grade for round brilliant diamonds and features innovative technology that measures the light performance of diamonds. AGS produces both Diamond Quality Certificates and Diamond Quality Reports.
  • Forevermark diamonds are graded at the Forevermark Diamond Institute in Antwerp, Belgium. The Forevermark Diamond Institute will only grade natural and untreated diamonds. As a De Beers subsidiary, Forevermark diamonds are sourced from mines that not only comply with their strict political, financial, social, and environmental requirements but also benefit the communities in which they are operating. The Forevermark Diamond Institute refers to their document as a Diamond Grading Report.
  • EGL (European Gemological Laboratory) USA’s main office opened in 1977 in the diamond district in New York and has established a reputation of fast turnaround time and fair grading standards and grades natural, synthetic and treated diamonds. E.G.L. refers to their report as a Certificate.
  • EGL International ­ founded in Belgium in 1974 and has a presence in most diamond exchanges throughout the world. EGL International is known to be more lenient in their diamond grading. E.G.L. International refers to their report as a certificate.

*Marks Jewelers is equipped with a long and short wave ultraviolet light box as well as a Sarin machine to determine the diamond’s fluorescence, polish, and symmetry.

  • July 3rd, 2019 By Dennis

    “Unbelievable, hassle free experience. From texting back and forth with Josh on a Saturday on the VIP event and the engagement ring options, to receiving and email from Dave that night with options for me to review to Tuesday going in and going in and purchasing while having a beer while I waited. Outstanding experience. Well done!”

  • June 26th, 2019 By John

    “I have been a customer of Marks jewelers for over 30 years. Over this time I have purchased many items from custom rings to bracelets. You cannot match the quality of the product that Jim sells This is now a family tradition. Both my son in laws and my son buy from Marks. Will go nowhere else for quality fine jewelry.”

  • June 19th, 2019 By Daniel

    “My experience at Marks Jewelers was wonderful. They created me a custom necklace that captured everything I could have possibly hoped for. The designers and Beth helped me work through my thoughts to create a piece that has deep meaning. Beth was amazing to work with and was patient with all my ideas. Thank you Beth and the team of designers.”

  • June 5th, 2019 By Jaki

    “The Marks in Montgomeryville is the only jewelry store that I trust with all my jewelry repairs and purchases. I make the 40 min drive every time because I know I'm going to get incredible service from anyone there and great prices.”

  • June 4th, 2019 By Amy

    “I can’t rave enough about my experience with Marks Jewelers. Olivia spent hours with me to design a couple pieces of jewelry with stones I had and Jacqueline created a couple of molds perfecting it. The end result is better than I ever imagined. My experience was so personalized and professional. Quality and a great price!!”

  • May 6th, 2019 By Lauren

    “My fiancé got my ring from there last August and it’s today my Dad and I went to turn my mom's wedding ring into my band and Jim was so helpful made me feel so comfortable and showed me exactly what the final product will look like! I’m so excited to receive my one of a kind wedding band! Marks is truly the best jeweler around!”

  • April 10th, 2019 By Ed

    “I needed a 3-tier tier pearl necklace restrung and I brought it to Mark's Jewelers. Although it is costume jewelry, it has much sentimental value to my wife. I wasn't sure if they would work on costume jewelry oh, but they did! They did a fantastic job! The drop-off and pick-up experience was terrific! Everyone was so professional. I highly recommend this place! I will be back!”

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