An Introduction to Gemology
The basic building blocks of understanding the science of gemstones.
Learn what gemologists do in our introduction to gemology. Whether your interest is casual or professional, the world of gems will amaze you.
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.
Gem formation usually involves mineral crystallization and other geological processes. Learn how these affect the gemstone properties gemologists study.
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 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.
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.
Gem identification is part detective work, part art. Learn how gemologists can distinguish gem species and determine whether a stone is natural or synthetic.
Crystals have habits. In crystallography, mineral habits refer to the way crystals form within a specific mineral. There are six crystal systems.
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.
Learn about the different crystal growth methods used to artificially create gemstones in laboratories.
Learn about synthetic diamond creation and the challenges buyers face determining whether a diamond is natural or artificial.
Many varieties of gems besides diamond can be created in the laboratory. Our synthetic gemstone guide covers many examples and explains their manufacture.
Identifying gemstone treatments is difficult even for experienced gemologists. Learn how they detect manufacturing traces and artificial enhancements.
Gemological formulas identify the chemical composition of gems and minerals. Learn what the symbols, numbers, and parentheses mean.
Even the most general definition of a gem has many exceptions. Learn what qualities have been used to identify gemstones both scientifically and popularly.
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? Take our short quiz and learn about the composition, cutting, and value of birthstones.
Gemstone identification requires a good reference library and some basic gemology tools. Before you go shopping, learn more about what you'll need.
Thinking of becoming a gemologist? A guide to opportunities for interesting, engaging, and beneficial careers in the world of gemology.
Learn how to organize your gemstone collection. Choose the storage and display options that are right for you and create a practical cataloging system.
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.
Gemologists sometimes measure gemstone density or specific gravity to help with gem identification. Learn the basics of this property and how to test it.
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.
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.
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.
Opals and pearls have special setting, cleaning, and storage needs. Our opal and pearl care guide will help you keep your jewelry beautiful.
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 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.
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 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.
Learn the scientific definition of crystal used by gemologists and answer some basic questions about what is and is not a crystal.
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 are materials trapped inside gems as they form. Learn how gemologists use inclusions to help identify gemstones and their sources.
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.
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 describes how much light passes through a gem and how it scatters. Learn what causes a gem to be opaque, translucent, or transparent.
Learn how lab grown sapphires are made and how gemologists can distinguish natural from synthetic sapphires.
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 has benefits and risks. Learn all about ultrasonic, steam, and boiling systems and how gems might react to them.
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 account for 95% of the world’s supply. Learn about Australia’s geological history, the start of its opal trade, and its sources.
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 is lovely, but aren’t these gems prone to scratching and breaking? Learn the best ways to wear these colorful but delicate stones.
Garnet species are always found as mixtures. Learn what’s distinctive about the rhodolite variety.
Should you wear chrysoprase jewelry only at night to protect the gem’s striking green color? Learn the facts here.
Learn what factors most influence a sphalerite appraisal and what kind of jewelry will best showcase this beautiful gemstone.
What does it take to become a professional gemologist? Try these sample gemology questions from the International Gem Society certification exam.
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.
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.
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.
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.
Your prized gemstones deserve custom faceting. Learn the benefits of working with precision faceters and tips for starting your own jewelry project.
Showcase the amazing inclusions in minerals like rutilated quartz in a gemstone pendulum design. Learn how to facet these gems into stunning jewelry pieces.
Satisfying the human desire for symmetry, trapiche gems have a special allure. Learn what makes these rarities so unique in our introductory article.
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.
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.
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 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.
Learn how diamonds formed geologically and how they became the virtual standard for engagement ring stones in this brief history of diamonds.