How to read and understand a diamond certificate?


Learn what a GIA certificate is and how to read it. The GIA, short for Gemological Institute of America, is the most highly regarded institution of the assessment and certification of diamonds.

What is a diamond certificate?

A diamond certificate lists all the main characteristics defining the stone´s quality and price.

Buying a certified stone is fundamental when in search of an engagement ring.

We ideally recommend that the certificate be issued by the Gemological Institute of America (hereafter the GIA) as it is the most recognized institute worldwide for the assessment and certification of diamonds.

MORE: Why do I need a diamond certificate?

My Diamond Ring sells GIA certified diamonds only

My Diamond Ring works exclusively with GIA certified diamonds to ensure that:

  • you are paying for exactly what you are getting
  • your diamond is ethically in line with the Kimberley Agreement
  • you will make a profit if you ever decide to resell your diamond. Over time, diamonds rise in value. So buying a GIA-certified diamond is always a good investment.

How to read and understand a GIA certificate?

There are usually 5 parts to a GIA certificate:

  1. GIA Natural Diamond Dossier
  2. Grading Results
  3. Additional Grading Information
  4. Proportions
  5. Grading Scales

NOTE: the paper form can look slightly different than the digital certificate, but both will contain exactly the same information.

Which section of the GIA certificate should I focus on?

Any diamond buyer should focus first and foremost on the Grading Results. The other sections are primarily informational.

#1 The GIA natural diamond dossier

This part can be compared to a person´s ID. It lists basic information about the stone and gives it an identification number.

  1. Date of examination
  2. Report number - this is the stone´s identification number. It is also engraved into the stone itself.
  3. Shape and cutting style - this defines the shape your diamond has been cut into. For example, round, oval, princess, etc.
  4. Measurements - defines the size of your diamond (i.e. height, width, and length) in millimeters.

#2 The Grading Results

This is definitely the most important part of a diamond´s certificate. This section lists the famous 4Cs, defining a diamond´s quality (and price!).

  1. Carat weight - the carat is often confused with a diamond´s size but it is actually a weight. Of course, the heavier the stone, the bigger, and also the more expensive it is.
  2. Color grade - defines how white a diamond is. White diamonds can be extremely white or have a yellowish tint. Whiter stones are more expensive.
  3. Clarity grade - defines how "pure" a diamond looks and measures the number of inclusions a diamond displays. The purer, the more expensive it gets.
  4. Cut grade - assesses how well a diamond was cut into its final shape. Better-cut diamonds are of course, more expensive.

NOTE: Fancy-cut diamonds (i.e. diamonds that are not round) are not given a cut grade by the GIA nor by any other grading institute because there are too many variations on each shape, making the cut grade difficult to assess.

#3 Additional Grading Information

This section of the GIA certificate lists further criteria defining the stone´s quality. Every criterion will also impact the stone´s price, but only in a minor way compared to the 4Cs described above.

  1. Polish - defines the smoothness of the diamond’s surface, "Excellent" being the best grade
  2. Symmetry - measures how symmetrical the shape, placement, and alignment of the facets are, "Excellent" being the best grade
  3. Fluorescence - examines how fluorescent a diamond is. 33% of all-natural diamonds exhibit fluorescence to a certain degree. We recommend going for a diamond whose fluorescence is graded as None, or Faint. Try to stay away from Medium, Strong, and Very Strong fluorescent diamonds as they may look milky, hazy, or even turn blue in direct sunlight!

Further information can also be shown in this section such as:

  1. Clarity Characteristics - names all the inclusions and blemishes present in the diamond. This basically gives added information as to which inclusions can be found in the diamond.
  2. Comments - e.g. detection of a treatment
  3. Inscriptions - texts, symbols, logos, GIA report number inscribed inside the diamond.

#4 Proportions

This section of the GIA certificate shows drawings of the actual diamond to help you visualize better its proportions and where its inclusions are located.

  1. Proportion diagram - this drawing is an actual representation of the diamond´s side view and shows detailed information as to the proportions of the stone; how thick the facets are; etc.
  2. Plotted diagram - this drawing is an actual representation of the diamond´s top view and shows where the inclusions and blemishes are located in the diamond.
  3. Key to symbols - this lists all the inclusions drawn into the plotted diagram, for example, crystal, needle, pinpoint, cloud, etc.

NOTE: The digital GIA certificate may not display the plotted diagram nor the key to symbols. Being subsidiary information, we recommend not worrying about it.

#5 Grading scales

These scales serve as a visual reminder of the grades given by GIA in order to help you locate better the color, clarity, and cut grades written in the Grading Results section.

  • GIA Color Scale
  • GIA Clarity Scale
  • GIA Cut Scale


The GIA certificate will also display security information:

  • Security Features (for document authentication)
  • QR-Code (for verification of the report against the GIA database)

Need help?

Finding your own diamond can be a daunting task. We, at My Diamond Ring, have created a list of buying guides to help you find the diamond that meets all your expectations in terms of quality and price!

READ: Diamond Buying Guides - all the tutorials you need to find your perfect diamond!