Diamond Certification - A complete Guide

What is Diamond Certification?

Diamond certification is when a gemological laboratory has evaluated the process and provides a certificate with impartial information about the quality and characteristics of that particular diamond, giving the buyer proof that the diamond is as the seller claims.

Loose diamonds are most commonly sold with certification. Loose diamonds that have been appraised formally are known as certified diamonds.

Quality characteristics of certified diamonds are documented in a grading report.

Header shows the Lab that graded the diamond.

The report number is a unique number assigned to the individually graded loose diamond upon which the report is based.

This refers to the shape of a loose diamond when viewed face up and cutting style of the loose diamond i.e. how the diamond’s facets are arranged.

It outlines the length, width and depth of the loose diamond.

It tells the weight of the loose diamond.

Rates from D-Z the least amount of colour that is in your loose diamond.

Rate from flawless to I3 how free a loose diamond is from blemishes and inclusions.

Rates from Excellent to Poor on how beautifully a loose diamond has been finished as part of the brillianteering process.

Rated from excellent to Poor on how beautiful the outline of the diamond is as well as how perfectly the facets have been created.

Measures loose diamond’s reaction when exposed under ultraviolet light. Typically rated from none, faint, medium, strong and very strong.

Lists micro-laser inscriptions on a diamond.

The proportions diagram outlines the technical measurements for the cut of the stone.

Security marks come in the form of a hologram, a universal product code or an embossed stamp.

Who Certifies Loose Diamonds?

Loose diamonds are certified by independent experts, who are trained in gemology. Diamond Certification are mostly from GIA, AGS, EGL IGI, GSI, and HRD.

It is a well known and reputed diamond grading lab. It is considered as a top gemological lab and loose diamond manufacturers send them their loose diamonds and gems from all around the globe for evaluation. GIA reports are highly recognized for their unbiased grading standards. Also, their consistency in grading loose diamonds is highly valued. A loose diamond with GIA certification can be trusted to be of good quality.

However, it takes long time for a loose diamond get through the GIA’s system to get certification.

It relishes on being the original lab to provide diamond cut grades and had been offering the same even before GIA had started. A loose diamond wasn’t termed as ideal unless it had AGS certification. The AGS lab is known for its scientific approach and research in diamond cut grading. Instead of using an alphabetical rating system, AGS uses a scale of 0-10 for rating a diamond’s characteristics, with 0 as the best and 10 as the worst.

AGS is well known for its consistency in grading system and they assess cut quality on a stricter standard compared to GIA. While their process is scientific in nature like the GIA, their diamond grades of GIA are stricter. In the US market, the AGS lab is the second most widely used lab service after GIA.

It is credited for introducing new approaches to diamond grading and has a large market share in Europe. An EGL certification helps customers in assessing the quality of loose diamond as it is a result of thorough evaluation of the diamond.

It is the largest independent gemological laboratory in the world and has locations in all major diamond centers. An IGI certificate dictates loose diamond's characteristics by several expert gemologists explicitly. IGI grades a significant amount of polished loose diamonds in the market and they are prevalent in Asian countries. IGI also grades synthetic diamonds on a commercial scale.

IGI labs in different countries use slightly different criteria while grading diamonds which result in inconsistencies in overall grading results. They are however improving their overall performance.

It has been around for only a few years. GSI also doesn’t maintain consistent grading.

It is a diamond grading organization based in Europe. HRD grading reports have a security feature which is a microscopic print visible only in UV light, protecting it from counterfeits.

Over the years, there has been a lot of inconsistency with HRD grading.

Different certification labs give different results:

Even though all diamond certification labs vary in their grading systems, GIA is considered to be more credible. Accurate certifications help in assuring customers that the loose diamond that they are purchasing is exactly what the jeweler is claiming.

AGS is also a good lab, but sometimes has inconsistencies in grading clarity and color. When it comes to grading diamond's clarity, AGS is more consistent compared to GIA as they use a proportions-based system.

IGI and EGL are decent labs, and are significantly cheaper than GIA and AGS certification. However, GIA and AGS are more consistent in their grading.

GSI and HRD usually average about two Color and/or Clarity grades above the GIA’s grading.

Always try to buy a loose diamond with a certificate from a highly reputed lab and review it thoroughly before making the purchase. The majority of certified loose diamonds in the U.S. are graded by GIA.

At Sanghavi Solitaire Inc., our goal is to help you purchase a diamond for a better price than any diamond wholesaler can offer. Every year there are millions of consumers who purchase GIA certified diamonds from various outlets across the world without comparing prices, and thus are overpaying. At Sanghavi Solitaire we try to deliver the best prices possible without sacrificing quality, helping you avoid unnecessary mark-up costs. Looking for a certain diamond or need advice? Call us now at 1800-234-1787.