International Gem Society

What’s the average gemstone faceting yield from a single piece of rough? Learn how to estimate how much material you’ll need to cut to get the…

You’ll find gem cutting acronyms like L/W in faceting guides. Learn what these frequently used terms mean and how they can save gem cutters time…

For millennia, artisans have carved intricate cameos from black-and-white onyx. Solid black onyxes, faceted or cabbed, are also popular jewelry…

This table contains a selection of minerals gemologists may encounter as jewelry stones or gem specimens. The gems are sorted by their crystal…

Measuring specific gravity helps gemologists identify gemstones. The following table lists the specific gravity values for a variety of gem…

How do you make money investing in gems? What should you buy, for how much, and how can you add value to your investments? Learn these top 5 rules.

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

While the colors of spessartite garnet gemstones cover a wide range of orange shades, the mandarin garnet is as pure orange as this variety can be.…

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.…

Refractive indices and double refraction (birefringence) help gemologists identify gems. The following table lists these values for selected…

Do you want to buy a diamond for an engagement ring? Don’t. Still want to buy a diamond? OK. Here are the pros and cons of buying a diamond online.

Diamond simulants, like cubic zirconia and moissanite, often appear in jewelry. See how the properties of real diamonds compare with popular…

Separate fact from fiction and you’ll find lab-created diamonds make great alternatives to mined diamonds. Our guide will show you how to shop…

The US Federal Trade Commission (FTC) can help jewelry marketers avoid making deceptive claims. Learn about the FTC diamond jewelry guide updates…

Blockchain tech can provide secure, digital transaction records. Can blockchain diamonds resolve ethical and legal issues related to sourcing…

NGOs and movies have helped raise awareness of conflict diamonds, and governments have taken steps to stop their trade. How effective are these…

Identifying diamonds requires the right equipment. Learn what diamond grading tools novice professionals or hobbyists need.

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

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

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…

Long associated with royalty, sapphires are some of the most popular (and expensive) gems in the world. Our sapphire buying guide will help you…

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

Some gems show pleochroism, two or three different colors depending on the viewing angle. Learn why this occurs and how it helps gemologists identify…

Whether you’re a novice bead jewelry maker or just shopping for necklaces, these bead and necklace size charts and links to related articles…

Looking for alternatives to a classic diamond engagement ring? Learn about your options and see some wonderful photos of colored gemstone engagement…

Will your gem fit in a standard setting? Use this chart of standard gem sizes for popular cuts and also learn how to estimate gem weight based on size.…

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 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…

The IGS survey results for polishing miscellaneous gems include recommendations for popular stones as well as gems seen less frequently in jewelry.…

Take a look at the IGS member survey results for opal polishing. You’ll find recommendations for polishes, laps, and techniques for handling these…

Popular jewelry stones, peridots can actually vary in hardness. Our IGS member survey results can help you choose the right tools and techniques…

The corundum gem family includes ever popular rubies and sapphires. Our IGS member survey results offer some corundum polishing recommendations.…

Cubic zirconia is the most popular diamond simulant currently available. You can find polishing recommendations for this material in our IGS…

Some very popular jewelry stones, such as beryl, quartz, and topaz, fall in the 7-8 hardness range. You can find polishing recommendations for…

Polishing feldspar, fluorite, apatite, or other gems in the 4-6 hardness range? Our IGS member survey results can recommend some techniques and…

Looking for lap, polish, or lubricant suggestions for quartz polishing? You can find numerous combinations and technical advice in our IGS member…

The GIA grading system describes gem color in terms of hue, tone, and saturation. Learn what the abbreviations and numbers of this gem grading code…

Using heavy liquids to measure a gemstone’s specific gravity poses some health hazards. Learn the techniques and precautions that gemologists…

You can use an electronic scale for calculating specific gravity if you have the right accessory, a hanging basket for measuring the weight of gems…

Using a balance scale to test specific gravity is a recommended practice in gemology. Learn to make your own scale or buy a Hanneman Specific Gravity…

Learn specific gravity testing methods for gem identification. Our 5-part introductory series starts with the basics and key definitions.

The idea of a single birthstone for each month is a modern idea with a long history, but today’s consumers can choose gems from traditional or modern…

Learn what gemstone dispersion means, what causes it, and how it relates to other optical effects of gems.

Novice and expert gemologists discuss their experiences at the celebrated annual February Tucson Gem and Mineral Show. You’ll find reviews of…

Rare chrome tourmaline can show an emerald-like green color. With a highly desired color and tourmaline’s excellent jewelry stone qualities,…

Although you can’t weigh a gemstone in a jewelry setting, you can get a close approximation of the gem weight by determining its volume.

Blue tourmalines or indicolites are a popular jewelry stone. However, some of these gems are often misrepresented.

Artists, lapidaries, and gem merchants all have stories to tell. Three very different books with varied perspectives explore the lives of people…

Looking for a tourmaline jewelry stone? If you like green and you’re on a budget, green tourmaline or verdelite is the gem for you.

Like all tourmaline gemstones, rubellite wears well in almost any type of jewelry. This stone’s raspberry-like color draws a great deal of attention.…

The International Gem Society (IGS) ran a jewelers’ pricing survey in 2002 and 2012. Over those ten years, we saw significant changes in the world’s…

Jewelry attachments are the pieces used to hold jewelry items together. Learn about the most popular types as well as miscellaneous decorative…

Earrings are available in many styles. Learn to identify the most popular types of metal and gem earrings and the parts that comprise these jewelry…

Though rings may come in many styles, gem cutters will regularly encounter a few common types of gem rings. Learn how to identify these popular designs.…

Bracelets and necklaces share much of their terminology. Learn the names and functions of the different parts of these popular types of jewelry…

The Mohs hardness scale measures a mineral’s resistance to scratching. Find the traditional scale here and a chart of select gems ordered by hardness.…

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

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.…

Wax opens a world of creativity for jewelers. Learn how to use centrifugal and vacuum casting techniques, tools, and machines to make wax models…

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 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.

Finding good diamond rough and the right equipment can be challenging for a non-professional diamond cutter. Learn what to look for here.

Polishing gemstones is difficult to master. Pre-polishing plays a major role in how well a gem can take a polish. Avoid scratches with these techniques.…

Fuzzy refractometer readings may be the result of poorly faceted gems, the wrong amount of refraction liquid, and even stone size. Learn more here.…

Appraising gemstones requires experience and an in-depth knowledge of gems. A list of gemstone wholesale prices is one element used in appraisals.…

What are the best techniques and tools for polishing girdles? Learn how to complete your faceted gems quickly and easily and avoid common errors.…

The glass used to make refractometer hemicylinders is susceptible to tarnish. Here’s a step-by-step guide for re-polishing a refractometer…

With the right tools and a little drilling know-how, you can create a rock lamp with an agate or jasper base, an oil lamp, and a glass lantern.

Diamonds may form under intense heat and pressure, but under certain conditions, diamonds burn.  Learn the science behind a diamond’s fiery…

Both natural and synthetic rubies fluoresce under UV light. Learn how slight differences in fluorescence patterns can help gemologists distinguish…

A ceramic lap is an excellent choice for polishing gemstones. Here is a guide for properly charging ceramic laps and avoiding scratching.

Do you have an offer for bargain rubies that’s too good to be true? Learn what you need to know before you buy and avoid high-pressure sales tactics.…

The Usambara effect is a gemstone color-change phenomenon distinct from pleochroism or the alexandrite effect. Tourmaline and other species…

Although Tanzania is a source of rubies, so-called Serengeti rubies are more likely to be garnets. Learn more about rubies and misleading gem names…

Choosing the best gemstone orientation for your rough takes skill and experience. Learn what factors you should take into account before cutting.…

Some opals from Spencer, Idaho show asterism or the “star stone” effect. Learn how to price these beautiful but rare star opals.

Polishing sapphire gemstones can be tough on laps. Learn the pros and cons of different laps and some techniques to save time and money.

Vapor deposition can be used to enhance gemstones like topaz and quartz with a metal coating or sheen. Learn how the process works here.

Uranium glass, or Vaseline glass, is a prized collector’s item and is generally safe to handle. But is it safe to facet? Learn about the potential…

Flint and mozarkite are types of chert. While flint is known for its practical use, mozarkite is a colorful variety of chert that can be made into…

Faceting wax or dop wax comes in different colors with different melting points. Learn how to choose the wax best suited for holding your gem for…

Polishing synthetic corundum without leaving pits requires certain techniques and tools. Get expert lapidary advice here.

In Exodus, the breastplate of Aaron was said to hold 12 gems. However, the gemological identities of the stones, like jacinth and sapphire, are…

What’s the best gem cutting machine for novices? Read about some popular models and learn the importance of finding the machine that’s right for…

Wax casting makes it possible to create intricate and unique metal pieces for jewelry. Here are some tips for beginners on a budget.

With study, care, and the right tools, hobbyist gem cutters can add diamond cutting to their repertoire. Get started with these tips from expert…

Is a flat lap to dop swing really necessary? Learn how a gemstone should contact a faceting machine lap and get some advice for adjusting your equipment.…

Turkey’s gemstones include well-known species such as diaspore, chalcedony, and jade, as well as unusual specimens of lesser-known gems. Learn…

To pick the right cut for a gem, you need to figure its maximum potential shape. Preforming gemstone rough is essential for making the design a reality.…

What’s the best doublet glue for creating assembled stone jewelry? Learn about the choices as well as tips for making the bond between gemstones…

Has your sterling silver money clip lost its spring? If you have experience with metalworking, learn these methods for repairing these popular…

Deep-cut gems like Barions may not fit in standard ring mountings. Jewelers can try to find special mounts or custom solder a mount from pre-made…

Oil treatment is a standard industry practice for enhancing emeralds. However, the treatments are not permanent. Learn how to re-oil emeralds…

Before you turn the alloyed gold you got a great deal on into gold jewelry, carefully consider what gold refining system will work best for you.

Working with platinum is actually a little easier than working with gold. If you want to add platinum jewelry repair to your metalworking skills,…

How does faceting affect gem value? Custom-cut gemstones are unique pieces and command a high price. Learn how custom cutting compares to factory…

Cutting tourmaline can be difficult. Some gems seem to shatter easily. Learn faceting techniques to minimize this risk as well as what equipment…

What’s the difference between a lab-created emerald and a natural emerald? Is a synthetic gem a real gem? Learn the facts before you buy emerald…

A quartz wedge can be used with a polariscope to help a gemologist distinguish the + or – optic sign of a gem. Learn how to make and use one.

An inexpensive pocket spectroscope can be great for student gemologists as well as pros who need to identify gems while traveling. Learn the basics…

Faceted dark colored gemstones can have intense colors but little brilliance. A simple formula can help a gemologist estimate a fair value for…

Aquamarine is the blue to blue-green variety of beryl. If you encounter so-called white aquamarines, buyer beware. Learn the facts about these…

Silk inclusions in sapphires are hard to detect. Learn to pick the best orientation and cut for these gems. You might end up with a prize star sapphire.…

These cleaning tips will make polishing silver jewelry a little easier. Learn how to prevent tarnish and how to clean silver and pearl jewelry,…

Gemologists may immerse gems in refraction fluids during examinations. This refractive index list of household liquids offers some common alternatives.…

What factors determine the light return of faceted gemstones? Facet quality, polish, color, and cut style all play roles. Learn more about these…

Emeralds get their green color from chromium and vanadium. Learn how the presence of these elements affects their formation and causes emerald…

A gemstone’s optic sign may be listed as either + or -. Learn whether impurities in a specific stone or the choice of axes to measure RI cause the change.…

Some gems are seldom faceted because they’re rarely found in nature or rarely used for jewelry. Learn a few tricks for faceting seven exotic gemstones.…

Cabochon cuts are popular for showcasing opal doublets. Learn a trick for making a bezel setting for doublets that are wider on top than the bottom.…

A classic chameleon diamond can change color from green to yellow under certain conditions. Learn more about this process and other color change…

Agate stones typically form slowly in the cavities of ancient hardened lava flows. Learn where you can see this process occurring today.

Many factors contribute to gemstone brightness. Learn the role a gem’s refractive index plays and the difference between gemology theory and…

Ring sizing is an important part of jewelry making and repair. Learn a few soldering and annealing tricks from the pros to master this skill.

Opals should be handled with care. If you buy opals that have been kept in water, follow these instructions to dry them safely.

Rubies and sapphires can be made in a lab. The process that yields the best synthetic corundum for faceting should give you the best return for your…

For faceting, the distinction between gems and minerals is usually clarity. However, learn why the decision to cut may be an aesthetic or even a…

What are the best facet designs for novice gem cutters? Find recommendations for cutting styles, books, resources, and gemstone rough here.

Dark green tourmaline and red rubellite gems can look very black in an emerald cut. Learn how to minimize this effect and show off these rich colors…

Curved striae or lines are a telltale sign of synthetic ruby and sapphire. If you’re having trouble seeing them, here are some helpful tips.

Natural alexandrite is rare, creating a market for synthetics. But are synthetics real alexandrite? Learn about natural, synthetic, and real…

Golden beryl, also known as heliodor, can display rich colors and is an excellent gem choice for jewelry. Learn more about this golden relative…

Gem repair is challenging but can also bring new life to vintage jewelry. Learn how to repair a cracked emerald with Opticon sealer and a small vacuum.…

Although emeralds and peridots are both green gems, differences in shade might make it hard to pair them in jewelry. Learn how to look for the right…

How do you start making a living in the jewelry trade? You need to learn gemology and metalsmithing and get serious about sales. Here are some tips.…

Did you know most gem species can be distinguished without the element of color? Learn the role gemstone colors play in gem identification.

Want to start cutting beautiful star gemstones? Here are some helpful gemological resources for novice lapidaries and jewelers.

Will wearing gemstones so they touch your finger bring you health benefits? Learn what to look for in a ring stone.

Learn how to cut a labradorite gemstone to showcase its striking color flash most effectively. Spectrolite is one variety that displays multiple…

Learn why citrine gemstones are sometimes misidentified as topaz. A professional appraisal by an independent gem lab is the best way to identify…

Can gemstone pricing formulas help gem merchants and buyers make fair deals? Learn what factors can affect gem prices.

Learn which rough gemstones are ideal for beginning faceting practice. A progression of relatively inexpensive gem species can teach important…

Gem faceters must consider factors like brilliance, color, and faceting yield before choosing a cut style. Learn what a Barion cut can bring to…

Where do the best rough sapphire stones come from? It depends on the color. Blue may be the most valued color, but these gems pose problems for faceting.…

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

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

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

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

Need insurance for your jewelry? You’ll need jewelry and gemstone appraisals. Learn what info they should include and who to trust with your…

How can you get lower gem and jewelry insurance quotes? Asking a potential insurer these few questions could help lower your premiums.

Your homeowner’s insurance may cover gems and jewelry, but don’t assume it covers all risks or the value of your items. Ask your insurer these…

Make gemology for kids educational and fun with these gemstone-themed games for all ages. Try these solo and party activities.

Our gemstone crossword puzzle collection is a fun and challenging way to test your knowledge of gemology, whether you’re an amateur or advanced…

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

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

We make recommendations about the best books to buy and read when getting started in faceting.

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

Although called “black diamonds,” carbonados are a polycrystalline material. Learn how they may have originated in ancient supernova explosions.…

Color change sapphires are those that change color between light sources.

Star sapphire is a type of sapphire that displays asterism, a star-like optical effect.

Padparadscha is a light to medium toned pink-orange to orange-pink hue sapphire.

Quartzite is a rock made up of tightly packed quartz grains. Sometimes, it contains small crystals that reflect light. This material is called…

Smoky quartz comes in every shade of brown, from a light tan to nearly black. This gem is known for its large sizes. If you want a really big gem on a very…

Microcline is a variety of feldspar. The only microcline you are likely to encounter is amazonite.

A few almandine/pyrope garnets from the US will change with treatment into proteus garnets. In reflected light, they have a dark gray, metallic…

Color change garnets are mostly pyrope and spessartite in composition. Except for the color change, they are identical in properties to the Malaia…

Rhodolite is a garnet, intermediate in composition between almandine and pyrope. Its distinctiveness lies in its color, which is nearly always…

Hydrogrossular differs from the other garnets in that it is never transparent. It ranges from translucent to opaque. The most common color is a…

Pyrope comes from a Greek word meaning “fire like.” The common dark red garnets are a mixture of pyrope and almandine.

Jasper is an opaque, solid or patterned variety of cryptocrystalline quartz. All types of jasper take an excellent polish, are trouble free to…

Marketed as “Gem Silica” this relatively rare, blue to blue-green, opaque to near transparent material is the most expensive type of chalcedony.…

Crocidolite, (blue asbestos,) alters to quartz, but while retaining its fibrous structure. This material is frequently stained by iron, giving…

The best-known and generally least expensive variety of chalcedony is carnelian. It ranges in color from yellow-orange to rich, near reddish…

Rubies versus Pink Sapphires. Both are varieties of corundum. Learn the true scientific difference between the two.

Lookup the current retail and wholesale price of any gemstone.

Learn about some gemstones said to have physical and emotional healing benefits.

Colored gemstone engagement rings are a trend that has been around for awhile, and the results are unforgettable and beautiful.

A brief explanation of the types of meteorites and where they come from, along with a history and discussion of meteorite jewelry and watches.

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

Idocrase is one of the lesser known and more beautiful collector gems. When properly cut it is as bright and attractive as the grossular garnets,…

A list of False or Misleading Gemstone Names and its Actual Gemological Name. Gathered by the source “Gemstones of the World, 3rd Edition, Walter…

Successful tips and guide in identifying Inclusions Found in Natural Gems. Read and learn several ways to identify inclusions found in natural…

A step by step procedure on how to make a bracelet. Detailed information on tools and materials needed. Read and Understand instructions to complete…

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

Tremolite runs in a solid-state series with actinolite to ferroactinolite. (Ferroactinolite is not used as a gemstone.) Details and information…

Ultra Tec Faceting Machine Review . The Ultra Tec has been referred to as the BMW of faceting machines. We had 1 tested by 3 people who own other brands.…

Vivianite is fragile and soft that cut gems would be difficult to handle safely,let alone wear.The color is very rich, and a few stones have been…

Faceting Survey Results for Polishing Sunstone: Get polishing methods for Sunstone. View results for various procedures in polishing Sunstone…

Faceting Survey Results for Polishing Topaz: Get ideas and methods on polishing Topaz. View results for various procedures in polishing Topaz…

Faceting Survey Results for Polishing Tourmaline: Get polishing methods for Tourmaline. View results for various procedures in polishing Tourmaline…

Faceting Survey Results for Polishing Garnet stones. Know the preferred polishing methods for Garnet. Also, view results for various procedures…

Polishing Beryls: Get successful tips, suggestions, and methods to polish a Beryl laptype, synthetic emerald laptype, or any gemstone of the…

Below are a number of comments, instructions, and hints that I thought would be of interest.  Enjoy:) Tin Lead lap with Linde A will polish more…

Spinel has played an important part in gem history. Prior to the last century, it was impossible to distinguish from ruby and sapphire once it was…

Sea shells are one of our most ancient decorations. Our prehistoric ancestors used to string them into necklaces or hang them from cords as pendants.…

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

Rhodonite is a popular and useful decorative material, ranging in color from pink to a fine rose-red.This article covers informative content…

A guide for the price of various gemstones that is based on various sources for commonly traded goods. However, gems are sold outside this range…

Glass comes in several natural forms. All are used in jewelry.

Laserblue is a rare, synthetic glass. It’s hard for glass but easy to chip.

In many ways buying a faceting machine is like buying a car. You probably would like the fanciest car on the road but would settle for a second hand.…

The transcription of the interview of International Gem Society IGS with C.D. Parsons of Santa Paula, Calif. and Gerald Wykoff GG, CSM.

The epidote group consists of 3 related minerals that are well known to collectors and hobbyists, plus 1 popular gem mineral and 3 less common species.…

Gahnospinel is a solid-state solution between spinel and gahnite.

This is a Gem Design Index. A list of several gem designs with details and instructions. Gather more information on various designs that are available.…

Diamond are our most popular gem. ts history of use and great value extends thousands of years into the past. Find out more on the properties of a diamond.…

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

Clinochlore is a family of minerals in the chlorite group. To date, only kämmerite and sheridanite varieties are known to have been cut as gemstones.…

Learn how to modify a powder scale for specific gravity testing. A handmade wire basket will make this easy-to-use scale a great tool for gemologists.…

When Identifying Inclusions found in Enhanced Gems, you have to be very careful when inspecting your stones. A clue is to find bubbles in the glue…

This year we asked our members for their impressions of the Tucson show. Here are their impressions. A little insight on the Tucson 2002 extravaganza.…

No one to date has a total inventory, or a complete database, of gems and all their properties. Gemologists need to be cautious about relying on any…

Before you buy jewelry and gemstone insurance, learn what to ask insurance companies and make sure the policy meets your needs.

This is a neat, simple, project that will teach you how to string beads with wire. You can take these skills and create bracelets, necklaces, earrings,…

A Bench Jeweler are artisans who sit in the back room patiently working on and carving Jewelry with very little to no acknowledgement on their work…

Hyperitdiabas is one of the most outstanding minerals I have encountered in recent years. Its appearance striking beautiful and a close inspection…

Birthstones listed by month. Also listed are both the Modern Birthstones and the Ancient Birthstones.

Printable chart to convert weights and measures including Carats, Grams, Kilograms, Ounces, Pounds and Troy Ounces Pounds and Pennyweights.…

A tabel of Lap Materials, Compliments of The International Gem Society. These figures are approximate and are put together for your general reference.…

Ring Size Comparison Chart compliments of the International Gem Society. A conversion table of Ring sizes. 7 different ring size equivalents…

A gem structure chart that shows various information on a specific structure and gems of example. Details include Refractive Indexes, Pleochroism…

Jewelers need to know how to determine how much gold is needed for a wax mold. Here are three methods for you.Information and tips on metal or wax formulas.…

A book review on “Gem Dealers Secrets”. It is always a treat to find a book that lives up to expectations and is entertaining to read. This is such a…

Gerald Wykoff has gained worldwide recognition for his “Master’s” series of gemological and lapidary books. The first, Beyond the Glitter, was…