What You Need To Know About Diamond Certification

A diamond certification begins with grading and evaluating a diamond to determine its value. Color, clarity, cut, and carat weight are the attributes of diamonds and are the 4Cs. Once diamonds are graded, a detailed report lists each one of the diamond’s attributes. Make sure the gemologist is certified by the Gemology Institute of America or GIA because it is your assurance that he or she maintains the highest code of ethics when grading and carrying out the diamond certification process.

Grading System

Established in 1931, GIA developed the International Grading System for accurately grading gemstones. It is an integral part of the diamond certification process. The GIA is trusted as the respected authority that educates and certifies gemologists. It takes a series of scientific tests and evaluations to perform the grading process on a diamond. Gemologists use sophisticated equipment to grade color, clarity, cut, and carat weight.


Before grading a diamond, the first step is to determine if it is natural or synthetic. A color scale establishes a diamond’s color and grades it from ‘D’ to ‘Z’. The ‘D’ grade is colorless while a ‘Z’ grade is light yellow to brown in color. The categories on the scale are colorless, nearly colorless, faint, very light, and light. Nearly colorless gemstones are widely used in jewelry. For accuracy in grading color, gemologists use a set of master gemstones that precisely match the color scale to compare and determine the grade of a gemstone.


When the gemologist looks at a stone, he or she is looking for internal and surface inclusions, which are natural forming characteristics or byproducts of the gem’s formation. Each inclusion gives diamonds their unique ‘fingerprints’. This scale has 11 clarity grades from ‘flawless’ to ‘I3’. A flawless gemstone has no inclusions while the grade ‘I3’ has inclusions visible to the naked eye. An example of an inclusion is ‘VS’, which stands for a Very Small inclusion. Gemologists use a jeweler’s 10X magnification loupe and a microscope to see inclusions and spot diamonds that received treatment to enhance their appearance. Inclusions noted on the grading report are part of the diamond certification process.


This step of the grading process determines the beauty and appearance of the diamond. The five ratings on the scale are excellent, very good, good, fair, and poor. The round brilliant cut is the standard when determining and grading the cut of a diamond. However, the rating scale applies to any cut of diamond. In addition to cut, gemologists look at a diamond’s light performance. The sparkle and brilliance of diamonds depend on their cut and polish, how light strikes the surface, and how much light returns to the eye from the diamond. All of these factors affect the appearance of a diamond.

Next, the diamond is rotated 360 degrees in order to create a 3-D model. Although there are no exact measurements that determine a well cut diamond, GIA uses a complex set of calculations to determine a diamond’s proportion. In addition to proportion, symmetry is another aspect of grading the cut of a diamond.

Carat Weight

One carat equals 200 milligrams or 1/5 of a gram in weight and larger stones are valued higher. For instance, a 1 carat diamond is worth more than four 1/4 carat diamonds put together. An electronic scale weighs to the fifth decimal place, and diamonds sold are at weights to the second decimal place-2.25 carats.

A grading report contains detailed information about the diamond and completes the diamond certification process. For access to the report, it is also online. As added insurance, a diamond can be laser inscribed with report number, message, or logo.

Why Certification

The purpose for diamond certification ensures that customers receive an accurate representation of diamond attributes and an assigned value according to the International Grading System criteria.

When purchasing a diamond, complete the diamond certification process and ask for the GIA certificate. As an added measure of assurance, confirm that the information on the GIA certificate by looking through a jeweler’s 10X magnification loupe. While diamonds are a symbol of lasting beauty, it is equally important to get what you pay for.

Author bio:

Ken Thomas is diamond jeweler and avid blogger who writes for numerous blogs including New Updates Weekly.

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