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.

Chinese jewelry piece - gem species and varieties
What are Gem Species and Gem Varieties?

Gem species are mineral species prized for their durability and beauty. Learn how chemical formulas and crystal structures define species and what causes gem variations, such as colors and optical phenomena.

fluorite with color zoning and phantoms - gem formation
Gem Formation: How are Gemstones Created?

Gem formation usually involves mineral crystallization and other geological processes. Learn how these affect the gemstone properties gemologists study.

Diamond - gemstone hardness
Gemstone Hardness and Wearability

Diamond is the hardest natural material in the world. However, it’s also brittle. Scientifically speaking, gemstone hardness measures the ability to resist scratching, nothing more. A gem's overall wearability grade takes its hardness into account. However, it’s only one of several factors to consider.

gem cutting styles - trilliant cut
A Guide to Gem Cutting Styles

Gem cutting styles refer to the shape and arrangement of facets. The three most basic styles are brilliant, step, and mixed. Learn what characterizes these types of cuts and how faceters combine them to create many different gem designs.

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 can distinguish gem species and determine 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.

sardonyx - birthstone gemology
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, cutting, 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.

spinel, Sri Lanka - gemology career options
Gemology Career Options

Thinking of becoming a gemologist? Consider these gemology career options, compare their estimated salaries, and decide which one may be right for you.

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.

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.

Crater of Diamonds State Park, AR - gem hunting in the US
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.

kunzite pendant - gemstone care guide
Gemstone Care Guide

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

rosaline pearl necklace - opal and pearl care guide
Opal and Pearl Care Guide

Opals and pearls have special setting, cleaning, and storage needs. Our opal and pearl care guide will help you keep your jewelry beautiful.

Esquel meteorite - a world of crystals
A World of Crystals

We live in a world of crystals. You don’t have to dig deep into the Earth to find them. Even the bones in our bodies and the dust in the air contain them. Learn more about crystalline minerals and gemstones as well as the crystals that grow in living beings.

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.

crystal group
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 - Dolomite and Rutile in Quartz
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 - sapphire ring
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.

quartz with inclusions - mechanical gemstone cleaning
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.

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.

trapiche gems - trapiche emerald necklace
Trapiche Gems: An Introduction

Satisfying the human desire for symmetry, trapiche gems have a special allure. Learn what makes these rarities so unique in our introductory article.

how to start a gem collection - gems in cases
How to Start a Gem Collection

Although many gem enthusiasts want to become collectors, they may not know where to begin. Read this article for tips on how to start a gem collection.

fancy gem cuts - oval-cut green diamond
An Introduction to Fancy Gem Cuts

Although rounds and other standard shapes dominate the gemstone market, fancy gem cuts offer many beautiful alternatives that can also improve a gem’s optical performance. Learn about the most popular fancy shapes, such as cushion, princess, heart, and emerald cuts.

gemstone facets - breaks, andalusite
Gemstone Facets: Terminology and Functions

Not only do gemstone facets create beautiful patterns on gem surfaces, they also help gems shine. While gem cutters will learn all about facets, all gem enthusiasts, especially gem buyers, can benefit from learning about facet types and functions.

lapidary arts - gem animal carvings
An Introduction to the Lapidary Arts

Lapidary is the art of working in stone. The term usually refers to the creation of small objects from gem materials. Read on to learn about the four basic lapidary arts: tumbling, cabbing, faceting, and carving.

diamond engagement ring and wedding band - history of diamonds
A Brief History of Diamonds

Learn how diamonds formed geologically and how they became the virtual standard for engagement ring stones in this brief history of diamonds.