Grading Gemstones and Diamonds


How to grade colored gemstones and diamonds including using the 4Cs --Color, Clarity, Cut, and Carat Weight.

A Consumer's Guide to Gem Grading

A Consumer's Guide to Gem Grading

Learn how gemologists evaluate color, clarity, cut, and carat for gem grading. Consumers can use this information to find the...
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Grading Gem Carvings

Grading Gem Carvings

Gem carvings are judged on material, workmanship, and artistry. Learn how to apply these criteria to a piece with our...
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Evaluating Gemstone Cutting: The Five Ps

Evaluating Gemstone Cutting: The Five Ps

In recent decades, something remarkable invaded the thinking process of the colored stone industry. From dealers to consumers, they all...
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Clarity Grading Diamonds

Clarity Grading Diamonds

Mastering clarity grading diamonds takes a lot of experience. This grading guide, with definitions, images, and examples, can help beginning...
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Diamond Rating: A Beginner's Guide

Diamond Rating: A Beginner's Guide

First-time buyers may not understand how diamond rating works. Our guide will teach you how diamonds are graded, so you...
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Distinguishing Diamonds: Educating Your Eyes

Distinguishing Diamonds: Educating Your Eyes

Distinguishing diamonds from their lookalikes requires educated eyes. Learn what visual features to look for and the properties of many...
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Modern Diamond Cut Grading Methods

Modern Diamond Cut Grading Methods

The GIA modern diamond cut grading method is the most widely accepted in the industry. Our step-by-step guide covers the...
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How to Grade Fancy Cut Diamonds

How to Grade Fancy Cut Diamonds

Fancy cut diamonds can have any finished shape, except round. These stones have their own grading criteria, in particular regarding...
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Traditional Diamond Cut Grading Methods

Traditional Diamond Cut Grading Methods

Traditional diamond cut grading methods prepare gemologists for making evaluations with minimal time, tools, and references. This step-by-step guide covers...
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Clarity Grading for Colored Gemstones

Clarity Grading for Colored Gemstones

Don't underestimate the importance of clarity, one of the Four Cs of gemstone grading. For faceted gems, basic clarity grading...
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How to Grade Set Gemstones

How to Grade Set Gemstones

Gems in jewelry settings can't be evaluated the same way as loose stones. These guidelines are for gemologists learning to...
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An Introduction to Gemstone Grading

An Introduction to Gemstone Grading

How goes gemstone grading work? Learn how gemologists evaluate both diamonds and colored gems and the qualities they examine.
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Advice for Determining Gemstone Value

Advice for Determining Gemstone Value

Judging gemstone value is complex, and new gemologists can have trouble with this. These four exercises can help you learn...
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Carats and Gemstone Grading

Carats and Gemstone Grading

Carats are the units used to measure gem weight and one of the main factors in gem grading. Learn what...
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Blue Tourmaline (Indicolite) Buying Guide

Blue Tourmaline (Indicolite) Buying Guide

Our indicolite buying guide can help you learn how these blue tourmalines are graded, what to avoid, and how to...
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Rubellite Tourmaline Buying Guide

Rubellite Tourmaline Buying Guide

Like all tourmaline gemstones, rubellite wears well in almost any type of jewelry. This stone's raspberry-like color draws a great...
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Chrome Tourmaline Buying Guide

Chrome Tourmaline Buying Guide

Rare chrome tourmaline can show an emerald-like green color. With a highly desired color and tourmaline's excellent qualities as a...
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Color Grading Fancy Colored Diamonds

Color Grading Fancy Colored Diamonds

The color grading standards for white diamonds don't apply to fancy colored diamonds. Learn the GIA and Argyle grading systems...
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Green Tourmaline (Verdelite) Buying Guide

Green Tourmaline (Verdelite) Buying Guide

Looking for a tourmaline jewelry stone? If you like green and you're on a budget, green tourmaline or verdelite is...
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The GIA Diamond Cut Grading System

The GIA Diamond Cut Grading System

How does the GIA diamond cut grading system work? Our guide will explain what the grades mean and how gemologists...
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Exposing Diamond Overgrading at EGL Labs

Exposing Diamond Overgrading at EGL Labs

The effects of the 2014 scandal over diamond overgrading at EGL labs are still emerging. Learn what gemologists and retailers...
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2018 Update to the FTC Diamond Jewelry Guides

2018 Update to the FTC Diamond Jewelry Guides

The US Federal Trade Commission (FTC) can help jewelry marketers avoid making deceptive claims. Learn about the FTC diamond jewelry...
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Can Blockchain Diamonds Solve Ethical Sourcing and Grading Issues?

Can Blockchain Diamonds Solve Ethical Sourcing and Grading Issues?

Blockchain tech can provide secure, digital transaction records. Can blockchain diamonds resolve ethical and legal issues related to sourcing and...
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FTC Guidelines for Grading Diamond Quality

FTC Guidelines for Grading Diamond Quality

The FTC requires jewelers to accurately represent the diamond quality grading systems they use. Learn the guidelines and protect yourself...
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Evaluating Diamond Cuts: The Hanneman Diamond Cut Grading System, Lesson Four

Evaluating Diamond Cuts: The Hanneman Diamond Cut Grading System, Lesson Four

The Hanneman System makes evaluating diamond cuts easier. You can use total height and C/P ratios to cut grade round...
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Cut Diamond Grade Categories: The Hanneman Diamond Cut Grading System, Lesson Three

Cut Diamond Grade Categories: The Hanneman Diamond Cut Grading System, Lesson Three

The Hanneman System simplifies cut diamond grade categories. Learn how to identify the worst cut stones quickly before taking unnecessary...
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Basic Diamond Proportions: The Hanneman Diamond Cut Grading System, Lesson Two

Basic Diamond Proportions: The Hanneman Diamond Cut Grading System, Lesson Two

In the Hanneman cut grading system, you must consider diamond proportions to grade a round brilliant stone. Learn what they...
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An Introduction to the Hanneman Diamond Cut Grading System, Lesson One

An Introduction to the Hanneman Diamond Cut Grading System, Lesson One

With the Hanneman diamond cut grading system, you can derive the cut grade of any round brilliant with minimal measurements...
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Color Grading White Diamonds

Color Grading White Diamonds

Mastering the art of color grading white diamonds is a challenge. Learn about the standards, terms, tools, and testing procedures...
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Common Sense Gemstone Grading: An Alternative System

Common Sense Gemstone Grading: An Alternative System

Can gem grading avoid subjective terms? Learn about gemologist Jeff Graham's common sense gemstone grading system, an alternative to commercial...
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Colored Stone Grading System

"Just Ask Jeff" shares his thoughts on the Color Stone Grading System of The GIA. In May 2008, he had...
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