The basic building blocks of understanding the science of gemstones.

introduction to gemology - jewelers
An Introduction To Gemology

Learn what gemologists do in our introduction to gemology. Whether your interest is casual or professional, the world of gems will amaze you.

Yugawaralite
Gem Species and Gem Varieties

Understanding Gem Species and Gem Varieties. This article introduces both concepts.

Crystalized Topaz and Quartz
Gem Formation: How are Gemstones Created?

An explanation of how gems are formed, and how and why gem quality crystals grow and change in nature.

Diamond - gemstone hardness
Gemstone Hardness and Wearability

Gemstone hardness measures a gem's resistance to scratching. Learn about this and other contributing factors to gem wearability or toughness.

Teardrop turquoise - gem cutting terms
Guide to Gem Cutting Terms

Tumbling, cabbing, faceting, and carving are the main fields of lapidary art. Learn about these techniques and basic gem cutting terms in this introduction.

gem classification - synthetic
A Guide to Gem Classification

Gemologists use several different gem classification methods. Learn how the most common systems work and what they cover as well as exceptions to the rules.

Oval Ruby - gem identification
An Introduction To Gem Identification

Gem identification is part detective work, part art. Learn how gemologists distinguish gem species and even whether a stone is natural or synthetic.

Sulfur - crystal systems
What are Crystal Systems and Mineral Habits?

Crystals have habits. In crystallography, mineral habits refer to the way crystals form within a specific mineral. There are six crystal systems.

Understanding Gem Synthetics, Treatments, And Imitations, Part 1: An Introduction

Tech advances and market forces make it essential for gem buyers to know the science behind synthetic gemstones and gem formation. Learn the basics here.

Understanding Gem Synthetics, Treatments, And Imitations, Part 2: Crystal Growth

Learn about the different crystal growth methods used to artificially create gemstones in laboratories.

General Electric Synthetic Diamond
Understanding Gem Synthetics, Treatments, And Imitations, Part 3: Synthetic Diamond

Learn about synthetic diamond creation and the challenges buyers face determining whether a diamond is natural or artificial.

Understanding Gem Synthetics, Treatments, And Imitations, Part 4: Synthetic Gemstone Guide

Many varieties of gems besides diamond can be created in the laboratory. Our synthetic gemstone guide covers many examples and explains their manufacture.

Understanding Gem Synthetics, Treatments, And Imitations, Part 5: Identifying Gemstone Treatments

Identifying gemstone treatments is difficult even for experienced gemologists. Learn how they detect manufacturing traces and artificial enhancements.

molecule model - gemological formulas
Understanding Gemological Formulas

Gemological formulas identify the chemical composition of gems and minerals. Learn what the symbols, numbers, and parentheses mean.

gem definitions - opal
What is a Gem?

Even the most general definition of a gem has many exceptions. Learn what qualities have been used to identify gemstones both scientifically and popularly.

Uncommon Elements Make Uncommon Gemstones

Why are some gems more rare than others? Learn how uncommon elements in the Earth’s crust help form uncommon gemstones.

How Well Do You Know Your Birthstone Gemology?

How well do you know your birthstone gemology? Take our short quiz and learn about the composition, faceting, and value of birthstones.

10x loupe - gemology tools
Recommended Gemology Tools and Instruments

Gemstone identification requires a good reference library and some basic gemology tools. Before you go shopping, learn more about what you'll need.

Lab-Gemology
Guide to Career Options in Gemology

Thinking of becoming a gemologist? A guide to opportunities for interesting, engaging, and beneficial careers in the world of gemology.

Gem Storage Case
Guide To Organizing Your Gemstone Collection

Learn how to organize your gemstone collection. Choose the storage and display options that are right for you and create a practical cataloging system.

rubies
Distinguishing between Rubies and Pink Sapphires

What’s the difference between rubies and pink sapphires? Learn about the chemistry of corundum and the history of the color pink. Then consider whether you’re buying or selling.

gemstone density - cerussite
Basics of Gemstone Density and Specific Gravity

Gemologists sometimes measure gemstone density or specific gravity to help with gem identification. Learn the basics of this property and how to test it.

Emerald Hollow
Top Spots For Gem Hunting In The US

Visit one of the top gem hunting spots in the US. Go alone or with the family. A gemology-themed vacation can be fun, educational, and (maybe) profitable.

Build Your Own Gemology Tools

Are you a hobbyist or professional gemologist facing high equipment costs? Read our IGS series of articles that can help you build your own gemology tools.

Gemstone Care Guide

Our gemstone care guide covers many popular gems. Learn how best to clean your gemstone jewelry and what kinds of stresses and cleaning methods to avoid.

Care Guide For Pearls And Opals

Pearls and opals have special setting, cleaning, and storage needs. Our care guide for pearls and opals will show you how to keep your jewelry beautiful.

A World of Crystals

We live in a world of crystals. Learn what diamonds, kidney stones, bones, pearls, and dust have in common.

gemstone birefringence - zircon
What is Gemstone Birefringence?

Gemstone birefringence is a measure of a gem's double refraction. Learn how it’s used to identify gems and see the effects birefringent gems can display.

California turquoise - Mojave Desert
Desert Prospecting: Discovering California Turquoise

Learn how one man discovered beautiful California turquoise gemstones by taking the time to appreciate Nature's beauty. Take his desert prospecting advice.

gemstone luster - talc various
What Is Gemstone Luster?

Gemstone luster describes how a gem's surface looks when it reflects light. Learn the common terms gemologists use for this property and what can affect it.

What is a Crystal?

Learn the scientific definition of crystal used by gemologists and answer some basic questions about what is and is not a crystal.

gemstone dispersion - cerussite
What is Gemstone Dispersion?

Learn what gemstone dispersion means, what causes it, and how it relates to other optical effects of gems. Check out some amazing dispersion examples, too.

Gemstone Inclusions - Apatite in Spinel
An Introduction To Gemstone Inclusions

Gemstone inclusions are materials trapped inside gems as they form. Learn how gemologists use inclusions to help identify gemstones and their sources.

malachite - idiochromatic gems
What are Allochromatic and Idiochromatic Gems?

Learn the difference between allochromatic and idiochromatic gems and why some gem species can occur in many color varieties and others occur only in one.

What Are Gemstone Absorption Spectra?

Learn how gems absorb wavelengths of light and how gemologists use gemstone absorption spectra to identify gems. There’s more to color than meets the eye!

gemstone transparency - carnelian
What Is Gemstone Transparency?

Gemstone transparency describes how much light passes through a gem and how it scatters. Learn what causes a gem to be opaque, translucent, or transparent.

What Are Lab Grown Sapphires?

Learn how lab grown sapphires are made and how gemologists can distinguish natural from synthetic sapphires.

How To Clean Your Gemstone Jewelry

A little gemology goes a long way. Learn how to clean your gemstone jewelry safely and how to deal with difficult jewelry settings and sensitive gems.

Mechanical Gemstone Cleaning

Mechanical gemstone cleaning has benefits and risks. Learn all about ultrasonic, steam, and boiling systems and how gems might react to them.

Spectroscope Instructions

The spectroscope is one of gemology’s principal tools. Our basic spectroscope instructions will teach you how to operate and calibrate this instrument.

Australian Opals

Australian opals account for 95% of the world’s supply. Learn about Australia’s geological history, the start of its opal trade, and its sources.

What Is A Reflectometer?

What’s the difference between a reflectometer and a refractometer? If you’re interested in studying or buying gems, learn the facts here.

Opal Jewelry Tips

Opal jewelry is lovely, but aren’t these gems prone to scratching and breaking? Learn the best ways to wear these colorful but delicate stones.

What Is A Rhodolite Gem?

Garnet species are always found as mixtures. Learn what’s distinctive about the rhodolite variety.

Does Chrysoprase Jewelry Fade?

Should you wear chrysoprase jewelry only at night to protect the gem’s striking green color? Learn the facts here.

Sphalerite Appraisal

Learn what factors most influence a sphalerite appraisal and what kind of jewelry will best showcase this beautiful gemstone.

Ruby Buying Guide

Our ruby buying guide can help you learn how rubies are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

Sapphire Buying Guide

Our sapphire buying guide can help you learn how sapphires are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

Topaz Buying Guide

Our topaz buying guide can help you learn how topazes are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

Opal Buying Guide

Our opal buying guide can help you learn how opals are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

3.60-ct spinel - spinel buying guide
Spinel Buying Guide

Our spinel buying guide can help you learn how spinels are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

Constellation - Oregon sunstone buying
Oregon Sunstone Buying Guide

Our Oregon sunstone buying guide can help you learn how these gems are graded and how to identify a high quality stone or a bargain in the rough.

Sample Gemology Questions - Brilliant Cut
IGS Certification Exam: Sample Gemology Questions

What does it take to become a professional gemologist? Try these sample gemology questions from the International Gem Society certification exam.

story gemstone - rhodolite garnet
Precision Faceting A Story Gemstone: Choosing Rough

A precision faceter can turn a rough stone into a story gemstone as unique as each client. Choosing the right rough is the first step in the design process.

gem design - sunshine stone detail
Precision Faceting A Story Gemstone: Gem Design

In the gem design stage of jewelry making, faceters evaluate a stone's qualities. Learn how to choose a cut for a gemstone as unique as your personal story.

faceting equipment - cutting concave facets
Precision Faceting A Story Gemstone: Faceting Equipment

Today's custom gem cutters use faceting equipment for precision work and design inspiration. Take a look at the toolkit of the new lapidary renaissance.

faceting process - dopping station
Precision Faceting A Story Gemstone: The Faceting Process

The faceting process turns rough stones into finished gems. Learn the steps custom faceters take to create unique gemstones that tell a client's story.

custom faceting - detail
Precision Faceting a Story Gemstone: Custom Faceting Advice

Your prized gemstones deserve custom faceting. Learn the benefits of working with precision faceters and tips for starting your own jewelry project.

gemstone pendulum - bronze rutile quartz pendant
Faceting a Gemstone Pendulum to Feature Inclusions

Showcase the amazing inclusions in minerals like rutilated quartz in a gemstone pendulum design. Learn how to facet these gems into stunning jewelry pieces.

sphalerite buying guide - round brilliant cut
Sphalerite Buying Guide

Our sphalerite buying guide can help you learn how these gems are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

peridot buying guide - Arizona peridot
Peridot Buying Guide

Our peridot buying guide can help you learn how these gems are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

old mine emerald in a modern ring - emerald buying guide
Emerald Buying Guide

Our emerald buying guide can help you learn how these gems are graded, what to avoid, and how to identify a high quality stone or a bargain in the rough.

lapis lazuli buying guide - brooch
Lapis Lazuli Buying Guide

Our lapis lazuli buying guide can help you learn how to grade these gems, what to avoid, and how to identify a high quality stone or a bargain in the rough.

amethyst buying guide - earrings
Amethyst Buying Guide

Long valued for its purple color and symbolic associations, amethyst is a versatile gem. Our amethyst buying guide can help you pick an excellent stone.