What is GIA Certification?

by Willyou.net * Jun 2, 2021
What is GIA Certification

GIA (Gemological Institute of America) is the leading gem lab in the diamond industry and the benchmark for all other certifications. A GIA certification is regarded as the most distinguished document a diamond can receive based on its 4C’s gemstone grading system. The certification measures each diamond on its clarity, color, cut and carat specs and is known for having the strictest and most consistent grading system. The certification is a full, scientific report that is an unbiased assessment of the diamond it’s grading. GIA is the world’s most respected gemstone laboratory, and a diamond containing the GIA certification is a renowned diamond. 

The History of GIA Certification

The Gemological Institute of America, GIA, was created in 1931 as the need for diamond and gemstone standards arose. Before then, there was an apparent lack of standard when it came to diamond evaluation. Diamond buyers had to trust their jeweler or cutter, whose diamond knowledge might not represent the highest of standards.

The establishment of GIA was a game-changer in the diamond industry. It changed the way both jewelers and the general public would come to know about diamonds. GIA’s founder, Robert M. Shipley, recognized the need for a standardized approach in grading diamonds and gems. He founded GIA as a gemology research institute as well as an education facility where gem knowledge could be shared with the public. 

GIA’s mission is to: “Ensure the public trust in gems and jewelry by upholding the highest standards of integrity, academics, science, and professionalism through education, research, laboratory services, and instrument development.” 

GIA has 14 locations, worldwide, in 13 different countries. A GIA certification can be acquired at one of its laboratories around the world. 

GIA Education

GIA’s diamond grading scale is categorized by their coveted 4 C’s: carat, color, clarity, and cut scale. Each diamond is analyzed and graded by at least two gemologists, based on these four qualities. 


The first step in the GIA certification process is weighing and measuring the diamond. GIA gemologists use an electronic micro-balance to weigh each diamond to gather the carat weight. They also use an optical scanning device to determine the exact measurement and proportion of the diamond. These devices provide the most accurate measurements of a diamond. 

A diamond is measured in metric carats where one carat is equal to 0.2 grams. This is approximately the weight of a paperclip. A carat is divided into 100 points. So, a 50-point diamond weighs .50 carats. 


GIA then grades the clarity of the diamond using specialized magnified equipment. The GIA clarity scale consists of 11 grades, ranging from ‘Flawless’ to ‘Included’. The GIA clarity grading system takes in consideration the size, nature, position, color, relief and quantity of clarity characteristics visible under 10× magnification. 

The following scale is GIA’s clarity-grading scale: 

  • Flawless (FL) – No inclusions or blemishes are visible to a skilled grader using 10× magnification
  • Internally Flawless (IF) – No inclusions and only blemishes are visible to a skilled grader using 10× magnification
  • Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult for a skilled grader to see under 10× magnification
  • Very Slightly Included (VS1 and VS2) – Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification
  • Slightly Included (SI1 and SI2) – Inclusions are noticeable to a skilled grader under 10x magnification
  • Included (I1, I2, and I3) – Inclusions are obvious under 10× magnification and may affect transparency and brilliance

GIA uses a diamond plot, mapping out a diamond’s flaws, both internally and externally. 


Color grade is determined by how white or colorless a diamond is. GIA grades diamonds on a letter color scale from D – Z. The less color a diamond has the higher the value it has. 

A diamond graded with the letter D represents a colorless diamond and continues up the scale to a diamond with the letter Z representing a light yellow or brownish tint. Each diamond is color graded by using controlled lighting and precise viewing conditions. 

GIA Color Scale left to right
GIA Color Scale Diamond demo
find the gia color scale in the gia report
Where to find the GIA color scale in the report


A diamond’s cut is an important factor in the GIA grading system, based on its fire, sparkle and brilliance. The GIA cut-grading scale is based on 7 components: brightness, fire, scintillation, weight-ratio, durability, polish and symmetry. 

Each of the 7 components is graded individually and based on the overall cut of the diamond. The cut grading scale is based on Excellent to Poor, depending on its range of proportions and angles. Because there are a variety of scores a diamond can receive, each diamond is graded according to all 7 components, shapes, and proportions for maximum fire and brilliance.

GIA Diamond diamond anatomy
GIA Diamond Anatomy

GIA Diamond Grading Report 

Every diamond that completes the GIA diamond grading system and receives a complete assessment of the stone’s 4 C’s: color, clarity, carat and cut, receives a GIA certification grading report. The diamond, itself, receives a laser-inscribed, GIA certification number with a diamond dossier certificate and can also be requested by the owner of the diamond. 

GIA Certificate Sample

The GIA report is printed with micro print lines, a hologram, and other security components before being laminated. This prevents any tampering of the document while preserving the certificate over time. The final report is placed in a protective sleeve and delivered back to the owner. 

GIA Diamond-Grading-certification-Report-gia certification

GIA Certification NYC

In order to get a diamond certified (or graded), anyone can submit a diamond to a GIA lab, worldwide. There are two GIA labs in the United States, located in New York City and Carlsbad. Having a diamond graded by GIA is a simple process that involves shipping the diamond to one of their labs. However, because of the issues involved in shipping, insuring and packaging diamonds, it is highly recommended to have a local jeweler submit the diamond on your behalf. 

Most diamonds in jewelry stores or online already have a GIA certification grading report, which can be requested at any time. It can be shown prior to purchasing a diamond and will be given along with the diamond after purchase.

GIA Certification Cost

Diamonds that are purchased from a local jeweler or online typically include the GIA grading report along with the overall cost of the diamond. But acquiring a GIA certification for a diamond, itself, isn’t too expensive. The report for a diamond weighing 0.70ct – 0.99ct costs around $48, and a diamond weighing the standard weight of 1 carat costs $110.  It’s a small price to pay for an insurance of a diamond. 

Benefits of a GIA Certification

The GIA is a highly respected certification and having a diamond certified through GIA has many benefits. First, the certification offers a reliable grading for the diamond. It also ensures that your diamond has been analyzed by the best in the diamond business, and that you’re receiving the diamond quality that is stated on the certificate. It provides a peace-of-mind about the authenticity of your diamond as well as the high security measures taken to grade the diamond.