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.
Understanding Gem Species and Gem Varieties. This article introduces both concepts.
An explanation of how gems are formed, and how and why gem quality crystals grow and change in nature.
Gemstone hardness measures a gem's resistance to scratching. Learn about this and other contributing factors to gem wearability or toughness.
Tumbling, cabbing, faceting, and carving are the main fields of lapidary art. Learn about these techniques and basic gem cutting terms in this introduction.
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 distinguish gem species and even 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.
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.
We live in a world of crystals. Learn what diamonds, kidney stones, bones, pearls, and dust have in common.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
Morganite has become a popular jewelry stone, especially for engagement rings. Our morganite buying guide can help you pick a great gem for any occasion.
No gem evokes the blue-green colors of the sea like aquamarine. Our aquamarine buying guide can help you choose the best gemstone for your jewelry project.
In this golden age of pearls, a wide variety of shapes, sizes, and colors are available. Our pearl buying guide can help you select a pearl you’ll love.
Revered for millennia, sky blue turquoise still has a dedicated following. Our turquoise buying guide can help you pick a gem for your next jewelry project.
Vivid color change makes alexandrite one of the world’s most coveted stones. Our alexandrite buying guide can help you find the best gem for your budget.
More than just a simulant for sapphire, tanzanite’s vivid hues have stunned the gem world. Our tanzanite buying guide can help you find a gem you'll love!
Decorative, patterned forms of agate are excellent natural gems. Learn more about agate's mesmerizing patterns in our agate buying guide!
Long valued for its brilliance, zircon is a natural and affordable beauty. Learn more about the quality factors for this gem in our zircon buying guide.
With sheen reminiscent of moonlight, moonstone is treasured across civilizations. Our moonstone buying guide can help you pick a gem for your next project.
Known for stunning, saturated hues, tourmaline is a colorful and modern gemstone. Read about quality factors for this gem in our tourmaline buying guide.
With so many colors and varieties available, garnet buying can be daunting. Whether starting your collection or completing it, our guide can help.
Deep-water coral displays bright, rich reds and delicate pinks. Our precious coral buying guide will help you choose a gem for your next jewelry piece.
Fancy colored yellow diamonds are becoming increasingly popular. Our yellow diamond buying guide has the information you need before your next purchase.