When looking for a loose diamond for a diamond engagement ring or a piece of diamond jewellery it is important to refer back to the diamond grading report that often will accompany the diamond – diamonds under 0.15 carats do not have reports issued. This certificate helps you as a consumer to be confident that what you are buying is described accurately by the seller and is often used for insurance purposes post-sale. In today’s article we look at what a diamond grading report is and how to read one.
What is a diamond grading report?
A diamond grading is an independent report that describes in detail the characteristics of an unmounted diamond or gemstone. How that information is referenced varies depending on the lab, but most grading reports contain: The 4Cs of diamond quality: colour, clarity, cut and carat weight.
What are the main laboratories?
There are various reliable gemological societies and associations that produce diamond grading reports. The most reliable and notable is the Gemological Institute of America known as the GIA. Other reputable grading labs include the American Gem Society (AGS), the European Gemological Laboratory (EGL)and the International Gemological Institute (IGI) is based in Antwerp, Belgium.
What does a diamond grading report contain?
A diamond grading report contains various sections that refer to specific element on which the report is based. We will use, as a guide, the certificate used by the Gemological Insitute of America (GIA) for illustration purposes. Although each lab will issue a different report, the general contents will be virtually identical.
Header of the Report – Who Graded the Diamond?
The header contains the name of the issuing laboratory. Certain labs are more respected than others and can also be known for specialising in specific types of diamonds e.g fancy coloured diamonds. We recommend purchasing diamonds that have been assessed by the most well known labs due to their quality and standards.
Report Number, Cutting Style And Measurements
A report number is a unique digit that is used for record keeping purposes. Labs will keep a record of this number on their system and allow you to enter the number online allowing for immediate verification that the report is real. Underneath the report number there will be information about the diamond’s characteristics, listed in this order: shape and cutting style and measurements.
The Four Cs – Classification And Attributes
The 4’s (Cut, Colour, Clarity and Carat) are the most well known aspects of a diamond report and list the assessment of each of these specific values that are assigned to the diamond.. The clarity grade is determined by a gemologist who examines the stone under 10X magnification for inclusions and imperfections. If the diamond is a standard 57 facets round brilliant, all reports dated after 2006 will include a cut grade.
Additional Grading Information
Additional grading information contains information that relates to more technical aspects of the diamond that affect its finish. The finish of a diamond refers to its appearance and the two factors that influence this are the polish and symmetry.
The polish rating grades the smoothness of the diamond’s surface – a well polished diamond producing crisper reflections. Symmetry, as the name suggests, relates to how well proportioned and aligned the stone’s facets are.
Finally, the last section grades the diamond’s fluorescence properties. The fluorescence of a diamond is described based on the intensity and the colour it glows with when exposed to ultraviolet (UV) light.
Reference Diagrams
Like our fingerprints, each diamond has its own unique characteristics. The clarity plot shows the blemishes or inclusions in the diamond which affect its clarity. Blemishes (external) are marked in green colour while inclusions (internal) are marked in red. Below this are the critical proportions of the stone indicated in a profile view. This proportions diagram is useful for people who wish to analyse the diamond based on numbers like table %, depth %, crown angles, pavilion angles and girdle thickness.
Security Features And Authenticity Marks
The final part of a report contains the security features that prove the authenticity of the certificate.Usually,, these security marks come in the form of a hologram, a universal product code or an embossed stamp.
At Diamonds Hatton Garden our team of family-run jewellers have assisted generations of clients to find their perfect large diamond engagement ring. Contact our team via harel@diamondshg.co.uk or call +44 7951 060238 for more information and to arrange your appointment. Alternatively, explore our selection of fancy coloured yellow diamonds for sale and if you are looking to buy fancy Pink diamond jewellery contact our team as well as viewing our latest Diamond earrings in Hatton Garden. Or contact our team to sell diamonds in London.