Certified Diamonds by Independent Gemological Laboratories

Certified diamond rings

Purchasing a diamond ring is a significant decision in one's life. Not only because of the emotional and romantic meaning associated with such a gift purchase, but also in terms of its financial value. It is thus advisable that prior to your important purchase you take look into and understand the importance of diamond grading reports and certified diamonds.

When buying a piece of diamond jewellery, whether this is a diamond engagement ring, a pair of diamond stud earrings or a diamond necklace, make sure that you're getting your money's worth for the diamonds purchased. Independent of whether the purchase is made online or in an actual jewellery shop, the item of diamond jewellery should be supplied with the corresponding diamond grading report. It is common practice for any reputable jeweller to provide a diamond grading report with the purchase of an item of diamond jewellery. The report is a statement that the diamond has been graded by an expert and has been certified to possess the stated characteristics.

Purchasing a certified diamond gives you the tangible assurance that the diamond set in the jewellery piece you are purchasing is of the quality stated by the seller. In contrast, diamonds without a diamond grading report come with no assurances as to the quality of the diamond. It is like purchasing a house with the deeds, or purchasing a car without the registration document.

Certified diamonds are diamonds that have undergone stringent analysis by a qualified diamond grader. Diamonds are graded in a gemological laboratory and are subject to a comprehensive assessment which determines the particular characteristics of the stone, including the 4Cs. Clarity, colour, cut and weight are among the indicators reported in a diamond grading report, also referred to as a diamond certificate. The diamonds used in all of our products have passed these rigorous tests.

Independent gemological laboratories issue diamond grading reports to give diamond buyers peace of mind when making that all important jewellery investment. With a diamond that's certified you can be confident that your purchase is of the quality and value stated by the jeweller.

Any jewellery item purchased from our website, which has a diamond of over 0.25 carat in weight is automatically issued with a diamond grading report from one of the internationally recognised gemological laboratories listed below. These laboratories are wholly independent, without any connection to diamond manufacturers or suppliers, including Congenial Diamonds.

At Congenial Diamonds we do not use enhanced diamonds, whether they've been colour adjusted or heat treated, in our jewellery.


Certification of smaller diamonds

A diamond grading report is usually not provided for stones under 0.25 carat. This is because the cost of the certificate would be too great in proportion to the cost of the diamond. However, we can provide grading certificates for smaller diamonds on request. Call us on 0845 548 9858 or email us if you need advice on purchasing quality diamond rings online.


GIA diamond certificate

Gemological Institute of America (GIA)


Established in 1931, the mission of the GIA is to protect buyers and sellers of diamonds by setting the standards used to evaluate this mesmerising gemstone. To this effect, in 1953 the GIA developed its world renowned Diamond Grading System and the 4Cs in an effort to accurately identify and characterise diamonds. These scales and standards were accepted as an international benchmark for comparing and evaluating the quality of diamonds and remain so until this day.

The GIA owns a number of laboratories that are used for grading diamonds, including New York, Mumbai, Hong Kong, Bangkok, Johannesburg and Israel. The average time for the issue of a diamond grading report is 3+ weeks. 

For a sample diamond grading report from GIA, please click here.



HRD Diamond certificate

HRD Antwerp - Institute of Gemology


HRD Antwerp is the European counterpart of the GIA. The abbreviation stands for "Hoge Raad voor de Diamond", which means Diamond High Council. It was established in 1973 to represent the Belgian diamond industry.

The HRD Antwerp diamond lab was set up in 1976. Since then, HRD Antwerp has been issuing diamond grading reports. In addition to diamond grading services, HRD Antwerp carries out research to support the diamond sector, as well as provides training courses on rough and polished diamonds and other gems.


GIE Diamond certificate

Gemological Institute of Europe (GIE)


The GIE has been serving the diamond industry for over 30 years. They have lab grading facilities in London, as well as in Antwerp. As the diamonds for our jewellery are sourced directly from wholesalers based in Antwerp, the diamond capital of Europe, the locations of these laboratories make it ideal for us to submit diamonds to the GIE for grading.

The GIE offers an online certificate validation facility, which gives an added level of assurance and confidence of the quality of the diamond purchased. The certificate number printed on the diamond grading report issued with the diamond can be entered online to verify that the information supplied on the report matches the records held on the GIE database. 



IGL diamond certificate

International Gemological Laboratories (IGL)


The IGL is a trusted gemological laboratory for diamond grading and gemstone identification, with offices in the UK, Antwerp, the Middle East and the US. Every diamond that is sent for grading is weighed, measured and graded in terms of its cut and clarity. At this point a certificate is issued with all the details of the assessment. For a sample of the IGL diamond report click here.

At Congenial Diamonds, we regularly use the diamond grading services offered by the IGL in London and in Antwerp. These locations are optimal for us as we source the diamonds for our products directly from Antwerp based diamond dealers and our workshop is located in the UK. 

Once a diamond or a gem is certified by the IGL and a grading report is issued, the certificate number of the report can be entered online to retrieve the original certificate and the details of the gem in question.  


IGI Diamond certificate

International Gemological Institute (IGI)


The IGI was established in Antwerp in 1975 to certify diamonds and other precious gemstones. Today the IGI has laboratories dotted around the world, including New York, Mumbai, Hong Kong and Tel Aviv.

To view a sample of the IGI diamond grading report click here.

The IGI also has schools of gemology in several countries. These schools offer a variety of courses in gemology for professionals and enthusiasts alike.



EGL Diamond certificate

European Gemological Institute (EGL)


The EGL was founded in Belgium in 1974. Since then it has been evaluating diamonds and issuing diamond reports to diamond dealers and jewellers. 

In support of the Kimberly Process, which prohibits the sale of diamonds mined in war zones, the EGL issues a Conflict Free Diamond declaration on its diamond certificates. This declaration is a statement that the diamond submitted to the EGL for grading and certification has been legally imported from legitimate sources according to the requirements of the World Federation of Diamond Bourses.

The EGL also offers online verification of their diamond grading reports.

For a sample diamond grading report from EGL, please click here.



Samples of Diamond Grading Reports


  • GIA
  • IGL
  • EGL
  • IGI 

  •  GIA logo

  • IGI logo

  • EGL logo

  •  HRD logo