Overview

A diamond without a grading report is a diamond you are taking on faith. The report is what turns subjective impressions — "it looks bright," "it seems clean" — into verifiable facts: this stone is G colour, VS2 clarity, Excellent cut, 1.52 carats. It is the common language that allows a buyer in London to compare a diamond graded in New York against one graded in Antwerp and make an informed decision.

This section of the encyclopedia covers grading reports from the ground up. It begins with the fundamentals: what a grading report is (and why the industry has largely stopped calling it a "certificate"), what information it contains, and how to verify that the report matches the stone in front of you. From there, it moves into a detailed, panel-by-panel guide to reading a report — the 4Cs summary, finish grades, fluorescence notation, the clarity plot, the proportions diagram, and the comments section where critical disclosures are often buried.

The second half of this section profiles the major gemological laboratories. GIA, HRD, and IGI each have their own grading philosophy, report formats, and areas of strength. Understanding these differences is not academic — it directly affects how you compare stones and what you should expect to pay. The section closes with a practical comparison of how and why grades diverge between labs, and where Arete Diamond draws its own quality lines.

Whether you are reading your first report or your hundredth, this section will sharpen your ability to extract the information that matters — and spot the details that others miss.

What You'll Learn

What a diamond grading report is, why it replaced the older notion of a "certificate," and what legal and practical weight it carries
The complete anatomy of a grading report: identification, the 4Cs panel, finish grades, fluorescence, measurements, the clarity plot, proportions diagram, and comments
How laser inscription and report numbers link a physical stone to its documentation — and how to verify that link online
How to read every section of a GIA report, including the symbols on a clarity plot and the implications of specific comment lines
The grading philosophies, histories, and report formats of GIA, HRD, and IGI — and how they differ in practice
Why two laboratories can assign different grades to the same diamond, and what that means for price comparisons
Which laboratories Arete Diamond accepts and why, and how our quality thresholds translate into the stones we offer

Featured Articles

Reports 101 — The starting point. What a grading report is, why the terminology matters, what the document contains, how the report number links to the physical stone, and how to verify any report online.
How to Read a Report — A panel-by-panel walkthrough of a diamond grading report. Shape and cutting style, measurements, the 4Cs summary, finish grades, fluorescence, the clarity plot and its symbol legend, the comments section, and the proportions diagram — each element explained so you know exactly what you are looking at.
Laboratory Profiles — In-depth profiles of the three major gemological laboratories: GIA, HRD, and IGI. History, grading philosophy, report types, and practical guidance on what to expect from each lab's documentation.
Lab Comparison — Why grades differ between laboratories, where the subjectivity lies, and how Arete Diamond navigates these differences when selecting stones and advising buyers.

Certificados y clasificación

Certificados 101

Cómo leer un certificado

Perfiles de laboratorios

Comparación de laboratorios