From the humble loupe to microscopes, spectroscopes and more. Learn about the tools of gemology here.

Amethyst with inclusions - 10X loupe
10X Loupe for Gemologists and Jewelers

The 10X loupe is the gemologist's best friend. Learn to examine gemstones for fractures, inclusions, color, and much more with this simple tool.

multipurpose microscope stage - complete
How to Build a Multipurpose Microscope Stage for Gems

A multipurpose microscope stage can help you move, view, and photograph gemstones under magnification easily from many angles. Learn how you can build one.

Portable devices for crossed filters gem testing
How to Build Pocket Crossed Filters for Gemstone Testing

The crossed filters technique allows gemologists to detect chromium in gems. Learn how to build a portable device for conducting this useful ID test.

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.

The Optical Spectrum and the Spectroscope

The spectroscope is a device that separates white light into an optical spectrum of component colors that can aid in gemstone and mineral identification.

The Dichroscope

The dichroscope is one of the most useful instruments a gemologist can have. Its primary purpose is to determine the pleochroism of a gem.

microscope - amber inclusions
The Microscope: A Guide for Gemologists

Sometimes, microscopic inclusions are the only way to tell natural from synthetic gems. Learn how gemologists can use a microscope for gem identification.

spectroscope - malaya garnet
The Spectroscope in Gemology

The spectroscope is a fundamental gemological tool. Learn how to use it to identify gemstones based on their absorption of different wavelengths of light.

gemstone refraction - synthetic spinel
Polariscope Guide, Part 1: Testing Gemstone Refraction

The polariscope is an essential tool for gem identification. Learn how it works, how to use it, and how to test gemstone refraction.

optic figure and sign - interference colors
Polariscope Guide, Part 2: Testing For Optic Figure and Sign

Learn how to use a polariscope to find the optic figure and sign of a gemstone. This is an important test for gem identification.

gemstone twinning - polariscope guide
Polariscope Guide, Part 3: Testing For Gemstone Twinning, Dichroism, and Crystal Strain

Learn how to use a polariscope to observe gemstone twinning, dichroism, and crystal strain, and then test your knowledge with a short quiz.

reticle - 20x magnification
Using a Reticle: A Guide for Gemologists

When combined with optical instruments, a reticle can take fine measurements. Learn how gemologists use this tool for measuring lengths and angles of gems.

How to Build a Home Gemology Laboratory

Learn what you need to set up a your own gem lab. You may be surprised to learn that this is easily within your reach, and doesn't need to cost a fortune.

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.

Review - Duplex II and Rayner Dialdex Refractometers
Product Review: Duplex II and Rayner Dialdex Refractometers

The Duplex II and Rayner Dialdex both make excellent refractometers for gemologists. How do they compare head-to-head? Learn more from our review.

Product Review, Gem Lab Refractometer

The Gem Lab Refractometer is an inexpensive and useful instrument for gemologists. Read our review to learn more.

Gemology Interactive Media Reviews

Have the information of authoritative gemology books at the click of your mouse. Our gemology interactive media reviews showcase three excellent examples.

product review - no name refractometers
Product Review: No Name Refractometers

Beware of cheap "no name refractometers" (and their distributors). These tools may not be suitable for gem identification. Read our review to learn more.

Product Comparison, Polariscopes

Polariscopes are one of our most useful instruments. They come in a wide variety of prices and qualities. There are a number of ways to make a polariscope.

Product Review, GL Spectroscope Lite

The GL Spectroscope Lite is a versatile, easy to use, and inexpensive tool for gemologists. Read our review to learn more.

Product Review, Diamond Calculator

There is a new piece of software available that will be of interest to many of you. It is called the Diamond Calculator. More information available here!

Product Review, Achiever Microscope

A microscope is an essential tool for gemologists. The Achiever Microscope is an excellent choice at a good price. Read our review to learn more.

refractive index testing - refraction
Refractometer Guide, Part 1: Refractive Index Testing

A gem refractometer is the best tool for refractive index testing. Learn how to use this instrument to conduct this and other gem identification tests.

GIA Gemset Hue Set
What Happened to the GIA GemSet Color and Hue Wheel?

The GIA GemSet offered plastic color masters for color grading gems. It's no longer in production. Software alternatives exist but still face limitations.

Gemology Reference Books: Reviews

Whether you’re an expert or novice gemologist or collector, add these gemology reference books we’ve reviewed to your library.

gemology book reviews - diamond cutter
Gemology Book Reviews: Careers

Learn how varied gemology careers can be. Our gemology book reviews highlight three books with different angles on this art, science, and business.

solitary ring and round diamond - diamond symmetry
How To Evaluate Diamond Symmetry

How can you evaluate diamond symmetry without an expensive proportion scope? Learn how to build an inexpensive alternative tool that will get the job done.

cabochon testing - amethysts
Refractometer Guide, Part 2: Cabochon Testing

Sometimes, analyzing cabochon gems with a refractometer requires different techniques than those for faceted gems. Learn these cabochon testing methods.

optic character - biaxial topaz
Refractometer Guide, Part 3: Determining Optic Character and Recognizing Optic Effects

Learn how to determine a gem’s optic character with a refractometer and how to identify optical effects you may encounter during gem identification tests.

“Genesis And Classification Of Agates And Jaspers: A New Theory” Book Review

“Genesis And Classification Of Agates And Jaspers: A New Theory” insightfully explains the formation of these gems and features beautiful photos.

Faceting Articles, Designs, & Pictures: Book Review

In Faceting Articles, Designs, & Pictures, renowned faceter Glenn Klein shares his insights on gem facet designs and the history of gem cutting in the US.

The Collector’s Guide to the Minerals of New York State: Book Review

The Collector's Guide to the Minerals of New York State is ideal for both experts and hobbyists. Its information, organization, and photos are first rate.

Gemstone Refractive Index And Refractometer Mini-Quiz

Test your knowledge of refractometer gem analysis with this mini-quiz. You can review material on any question you miss at the end of the quiz.

amateur gemstone faceting - pre-polish
Amateur Gemstone Faceting Volume 1: Book Review

Amateur Gemstone Faceting Volume 1 provides a much-needed modern introduction to faceting for novices. Learn how instructors and students alike can benefit.