DIAMOND EDUCATION

Diamond Certification Guide

A diamond grading report provides independent information about a diamond’s characteristics, including its carat weight, colour, clarity and proportions. Learn how to read a diamond report, understand the information it contains and compare diamonds with greater confidence.

What Is Diamond Certification?

A diamond certificate, more accurately called a diamond grading report, is a document issued after a diamond has been examined by an independent gemological laboratory.
The report records important characteristics of the diamond and provides a consistent way to identify and compare individual stones. Depending on the laboratory and report type, it may include information about carat weight, colour, clarity, measurements, proportions, fluorescence and other identifying characteristics.

Why Is a Diamond Grading Report Important?

A grading report gives you independent information about the diamond rather than relying only on its appearance or a seller’s description.
It can help you compare diamonds with similar specifications and understand why two stones of the same carat weight may differ in appearance and price.
A grading report is especially useful when choosing a centre diamond for an engagement ring because it provides documented information about the characteristics of the individual stone.

This Diamond Certification Guide explains the information found in a diamond grading report and how it can help you compare individual diamonds. By understanding the terminology, grades and measurements shown on a report, you can make a more informed decision when choosing a diamond for an engagement ring.

GIA Diamond Grading Reports

GIA — Gemological Institute of America is one of the best-known gemological organisations associated with diamond grading and education.

A GIA grading report can provide detailed information about a diamond’s characteristics and measurements, allowing the stone to be identified and compared with other diamonds.

For natural diamonds, the report may include the diamond’s colour, clarity, carat weight, proportions and other grading information depending on the report type.

IGI Diamond Grading Reports

IGI — International Gemological Institute also provides grading reports for diamonds, including natural and laboratory-grown diamonds.

An IGI report can contain information about the 4Cs, measurements, proportions and other characteristics of the stone.

For a laboratory-grown diamond, the report identifies its laboratory-grown origin.

Natural and Lab-Grown Diamond Certification

Both natural and lab-grown diamonds can be evaluated by gemological laboratories.
The grading principles used to describe characteristics such as colour, clarity and carat weight allow buyers to compare individual stones more easily.
One important distinction is that a laboratory report for a lab-grown diamond should clearly identify its laboratory-grown origin.

How to Read a Diamond Certificate

When reviewing a diamond grading report, look at more than just one grade.

Important information may include:

Report Number — identifies the specific grading report.

Carat Weight — the weight of the diamond.

Colour Grade — describes the diamond’s body colour.

Clarity Grade — evaluates inclusions and blemishes.

Measurements — records the dimensions of the diamond.

Proportions — may include depth, table and other measurements.

Polish and Symmetry — describe aspects of the diamond’s finish.

Fluorescence — records the diamond’s reaction to ultraviolet light where applicable.

Does a Certificate Determine Whether a Diamond Is Beautiful?

A grading report provides valuable technical information, but diamonds with similar grades can still appear different.

Shape, proportions, facet arrangement and personal preference also influence how a diamond looks when viewed and when set into an engagement ring.

That is why certification should be considered alongside the 4Cs, diamond shape and the ring setting.

How to Verify a Diamond Report

Many major gemological laboratories provide online report-verification services.

Using the report number, you can check whether the information on the physical or digital report corresponds with information held by the issuing laboratory.

Verify a GIA report

Verify a IGI report

Choosing a Certified Diamond

As explained throughout this Diamond Certification Guide, a grading report provides valuable information when comparing diamonds, but it should be considered alongside the diamond’s appearance, shape, cut and your personal preferences.
At TONOUS Jewellery, you can explore engagement-ring designs and compare different diamond characteristics to find the combination that best suits your preferences.