Donald Clark, CSM IMG
Founder
Donald Clark, CSM founded the International Gem Society in 1998. Donald started in the gem and jewelry industry in 1976. He received his formal gemology training from the Gemological Institute of America (GIA) and the American Society of Gemcutters (ASG). The letters “CSM” after his name stood for Certified Supreme Master Gemcutter, a designation of Wykoff’s ASG which has often been referred to as the doctorate of gem cutting. The American Society of Gemcutters only had 54 people reach this level. Along with dozens of articles for leading trade magazines, Donald authored the book Modern Faceting, the Easy Way.
Articles by Donald Clark, CSM IMG
Cabochon Carving Tools and Techniques
Whether you're creating a simple gem accent or an exquisite cameo, the tools and techniques of cabochon carving are the...
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Gemstone Dopping Techniques
A novice gem cutter needs to master various dopping techniques for cabbing and faceting gemstones. Learn how to attach gem...
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Polishing Metals: An Introduction
Getting a brilliant polish is one of the most important steps to finishing fine jewelry. Learn the tools and techniques...
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Soldering Precious Metals
Soldering is one of the most useful techniques a metal smith can have. It is used both to create new...
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Gemstone Color Change Phenomena
Why do certain gems change color under different lights? Explore gemstone color change phenomena and the difference between natural and...
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Appraising Opals
Opals are unique gems with their own unique terminology. Learn the modern standard system for classifying and appraising opals used...
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What is a Gem?
Even the most general definition of a gem has many exceptions. Learn what qualities have been used to identify gemstones...
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An Introduction to Gemstone Grading
How goes gemstone grading work? Learn how gemologists evaluate both diamonds and colored gems and the qualities they examine.
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Appraising Gems and Jewelry
Appraising gems and jewelry involves opinions of value based on knowledge and research. Learn what information gemologists should include on...
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Tips and Tools for Handling Gems Securely
These tips and tools for handling gems securely will help novice gemologists and gem cutters reduce the risk of dropping...
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Basic Jewelry and Gem Appraisal Terms: What is Value?
Many people assume that a gem appraisal sets a definitive price for an item. Actually, the price depends on the...
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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...
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Glass Value, Price, and Jewelry Information
Glass has been used in jewelry for thousands of years. By itself, glass is brittle and unimpressive with very little...
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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...
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Advice for Determining Gemstone Value
Judging gemstone value is complex, and new gemologists can have trouble with this. These four exercises can help you learn...
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Carats and Gemstone Grading
Carats are the units used to measure gem weight and one of the main factors in gem grading. Learn what...
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Money-Saving Ways to Clean Jewelry
Some household products and do-it-yourself methods can clean jewelry safely and save you money. Discover the common ingredients in some...
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Product Review: GL SpectroLite
The GL SpectroLite is an inexpensive and easy-to-use tool that can help gemologists conduct spectroscope exams. Read our review to...
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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...
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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...
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Phenomenal Gems: Cat’s Eyes, Star Stones, and More
Phenomenal gems seem to do magical things with light. Learn the science behind optical effects like cat’s eyes and star...
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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...
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Product Review, Gem Lab Refractometer
A refractometer is an important tool for gem identification. The Gem Lab refractometer is an inexpensive model that’s a good...
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Lapidary Fundamentals: Cutting Rough Stones
Learn the best techniques and tools for cutting rough stones. Making small pieces from big pieces is one of the...
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Lapidary Fundamentals: Cabochon Cutting
Cabochon cutting or cabbing is the most popular form of gem cutting. With practice, you can master this skill. Read...
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Lapidary Fundamentals: Gemstone Tumbling
Gemstone tumbling is the simplest and least expensive lapidary art to learn. These guidelines can help you choose the right...
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Product Review, Achiever Microscope
A microscope is an essential tool for gemologists. The Achiever Microscope is an excellent choice at a good price. Read...
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Lapidary Fundamentals: Gemstone Faceting
Learn the basic procedures of gemstone faceting. This walkthrough for a standard round brilliant cut gem includes cutting instructions and...
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Angles for Cutting Garnets
Cutting garnets and other color saturated gems for brilliance can be challenging. Here's some advice for choosing the best angles...
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Choosing Faceting Angles
With so many recommended faceting angles, new gem cutters can have a hard time choosing one. Learn the basic guidelines...
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Identifying Synthetic Gems
Distinguishing between natural and synthetic gems is a critical skill for gemologists. Learn about gem making processes and the telltale...
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Paraíba Tourmaline Value, Price, and Jewelry Information
Discovered in 1989, paraíba tourmalines are among the world’s most prized gemstones. These rare gems are renowned for showing intense...
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Color Grading Fancy Colored Diamonds
The color grading standards for white diamonds don't apply to fancy colored diamonds. Learn the GIA and Argyle grading systems...
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Choosing the Right Cut: A Faceter’s Guide
Choosing the right cut for a piece of gem rough is an art. Learn how to balance brilliance with color...
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A View of the Quartzsite Gem Shows
The Quartzsite gem shows attract gemologists and rock hounds from around the world. Learn what to expect and how to...
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Difficult Gemstone Separations
Two of the trickiest gemstone separations to make are scapolite from citrine and apatite from tourmaline. Learn some tips for...
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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...
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Combining Stones in Jewelry
Combining stones can be more than adding diamond accents to colored gemstone jewelry. Explore colored stone combos and learn how...
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Identifying Synthetic Diamonds
Although most manufacturers disclose their synthetic diamonds, some resellers don’t. Learn how to identify these lab-created diamonds.
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Gemstone Identification Quizzes: Testing Procedures
Gemstone identification can involve many tests. These quizzes can help novice gemologists learn to pick the appropriate ones and identify...
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Buying Gems: Test Your Identification Skills
When buying gems, gemologists must temper their excitement with an analytical eye. Test your gem identification skills with these quizzes....
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Gemology Cheat Sheets
These gemology cheat sheets review gem color and clarity grading, specific information on evaluating diamonds and opals, and basic gem...
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Gemstone Visual Examination Quizzes
A visual examination is the first step to identifying a gemstone. These quizzes will help student gemologists learn to recognize...
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Gemstone Refractometer Mini-Quiz
Test your knowledge of refractometer gem analysis with this mini-quiz. You can review material on any question you miss at...
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A Gem Identification Quiz for Novice Gemologists
Learning how to identify gems involves more than just data. This gem identification quiz can help novice gemologists learn how...
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The GIA Diamond Cut Grading System
How does the GIA diamond cut grading system work? Our guide will explain what the grades mean and how gemologists...
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Gemstone Examination Lesson
Learning how to conduct a gemstone examination takes practice. Follow an expert gemologist step-by-step through tests of five unknown samples....
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The Microscope: A Guide for Gemologists
Sometimes, microscopic inclusions are the only way to distinguish natural from synthetic gems. This makes the microscope an essential lab...
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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...
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Refractometer Guide, Part 3: Determining Optic Character and Recognizing Optic Effects
Learn how to determine a gem’s optic character with a refractometer and identify optical effects you may encounter during gem...
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Dichroscope Guide for Gemologists
The dichroscope is one of the most useful instruments a gemologist can have. Its primary purpose is to determine the...
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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....
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Ultraviolet Testing and Gemstone Identification
Ultraviolet testing can be crucial for gemstone identification. Learn the basics of this technique as well as how to make...
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The Spectroscope
The spectroscope is a fundamental gemological tool. Learn how to use it to identify gemstones based on their absorption of...
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Jewelry Metals 101: Gold, Silver, and Platinum
Gold, silver, and platinum are the most commonly used jewelry metals. Learn about their physical properties, alloys, and history.
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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...
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Polariscope Guide, Part 3: Testing for Gemstone Twinning, Dichroism, and Crystal Strain
You can use a polariscope to observe gemstone twinning, dichroism, and crystal strain. Test your ability to identify these and...
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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...
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Polariscope Guide, Part 1: Testing Gemstone Refraction
The polariscope is one of gemology’s simplest and most useful tools. With a little practice and our three-part polariscope guide,...
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Gemstone Physical Properties
The optical properties of gems attract our eyes and can give a cut stone a unique character. However, gemstone physical...
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Gemstone Optical Properties
Learn how gemstone optical properties, like refractive index and pleochroism, help gemologists identify gems and lapidaries choose cuts.
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Enhanced Gem Inclusions
Gem treatments can affect a stone’s value and stability. Learn how the most common procedures work and how to identify...
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Corundum Treatments
Corundum gems receive more types of treatments than any other stones. Learn how to test rubies and sapphires for signs...
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How to Test for Diffusion Treated Gems
Learn how to spot diffusion treated gems with a simple immersion test. This common treatment for sapphire can significantly reduce...
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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...
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Destructive Gemstone Tests: Acid Testing
Acid testing is a destructive procedure gemologists can use to determine if some pieces are real or fake. Learn how...
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HPHT Diamond Treatments
HPHT diamond treatments can only be positively identified with costly equipment. However, you can learn to assess the probability that...
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Center-Fused Color Treated Gemstones
Center-fused color treated gems are assembled from natural rough. Learn how the procedure works and how to identify this stable...
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A Beginner’s Guide To Common Gemstone Heat Treatments
Gemstone heat treatments can increase the beauty and value of many rough pieces. Learn how to conduct the most common...
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Identifying Garnets Simplified
Identifying garnets by species is complicated. Learn how to use refractive index, hue, and absorption spectrum readings to simply the...
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Destructive Gemstone Tests: Dye Testing
Gemologists can use dye testing to determine if a gemstone has been dyed to alter its color. Learn how to...
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What are Gemstone Enhancements?
Gemstone enhancements improve the appearance and wearability of gems. Learn about the most commonly used procedures and frequently treated types...
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Destructive Gemstone Tests: Hot Point Testing
Gemologists use the hot point test to determine if a piece is a plastic imitation or coated in wax. Learn...
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Destructive Gemstone Tests: Scratch Testing
Gemstone scratch testing can help determine the Mohs hardness value of a mineral sample. Learn how to conduct this destructive...
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A Consumer’s Guide to Gem Grading
Learn how gemologists evaluate color, clarity, cut, and carat for gem grading. Consumers can use this information to find the...
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The Minimum Cutting Technique for Gemstones
The minimum cutting technique will help you get the largest gems possible from rough. Learn how to deal with internal...
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Inclusion Management and Gemstone Faceting
Inclusion management is one of the most challenging aspects of gemstone faceting. Learn when to remove and when to keep...
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Disclosing Enhancements: A Gemologist’s Guide
Disclosing enhancements to gems is a key duty for gemologists. Learn what are the hardest treatments to detect and how...
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Carving Techniques for Handling Inclusions in Transparent Gems
Inclusions don't have to result in a loss of mass or value when cutting transparent gems. Learn how to manage...
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The Gemstone Butterfly Cut
The Gemstone Butterfly is a stunning design for a custom-cut gem. Our step-by-step guide will show you how to facet...
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Diamond Buying Guide – Special Free Preview
First-time gem buyers may find diamond grades confusing. Our consumer guide explains how diamonds are evaluated and gives advice on...
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Frosted Stars: Variations on Star-Cut Gemstones
“Frosted Stars” are variations on classic five and six-pointed star-cut gemstones. Learn how to facet these gem designs and make...
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How to Add Sparkle to an Emerald Cut
Add sparkle to an emerald cut with a new cutting technique. You can apply this design to gemstones with standard...
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Destructive Gemstone Tests: Streak Testing
Streak testing is a destructive gemstone test rarely used by gemologists. Most gems leave no streak. Learn which gems do...
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Calcareous Concretions Value, Price, and Jewelry Information
Several species of marine mollusks produce stony growths called calcareous concretions or non-nacreous pearls. Varieties such as conch pearls, tridacna...
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Tips for Cabbing and Carving Opals
Opal cabochons can fetch high prices but may be difficult to cut. These tips for carving opals can help gem...
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Grading Gem Carvings
Gem carvings are judged on material, workmanship, and artistry. Learn how to apply these criteria to a piece with our...
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Uncommon Elements Make Uncommon Gemstones
Why are some gems so rare in nature? Learn which elements in the Earth’s crust are the rarest and how...
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10X Loupe for Gemologists and Jewelers
The 10X loupe is the gemologist's best friend. Learn how to examine gemstones for fractures, inclusions, color, and much more...
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An Introduction to Gemology
Learn what gemologists do in our introduction to gemology. Whether your interest is casual or professional, the world of gems...
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How to Grade Fancy Cut Diamonds
Fancy cut diamonds can have any finished shape, except round. These stones have their own grading criteria, in particular regarding...
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Recutting Diamonds and Colored Gemstones
When is recutting diamonds and other gems worthwhile for a professional gemologist? Learn how to make this determination and avoid...
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How to Grade Set Gemstones
Gems in jewelry settings can't be evaluated the same way as loose stones. These guidelines are for gemologists learning to...
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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.
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Distinguishing Diamonds: Educating Your Eyes
Distinguishing diamonds from their lookalikes requires educated eyes. Learn what visual features to look for and the properties of many...
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Choosing, Rating, and Grading Diamonds
First-time gem buyers may find diamond grades confusing. Our consumer guide explains how diamonds are evaluated and gives advice on...
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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...
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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...
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Chicken-Blood Stone Value, Price, and Jewelry Information
One of the most prized ornamental materials in China, chicken-blood stone has been used for centuries to create carvings with...
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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...
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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...
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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...
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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...
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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...
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Identifying Inclusions of Specific Gems
Some natural as well as synthetic gems have specific, characteristic inclusions. Learn the identifying inclusions of some of the most...
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Take the Birthstone Quiz
What do you know about birthstones? Take our short birthstone quiz and learn about the makeup, cutting, and value of...
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Modern Diamond Cut Grading Methods
The GIA modern diamond cut grading method is the most widely accepted in the industry. Our step-by-step guide covers the...
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Traditional Diamond Cut Grading Methods
Traditional diamond cut grading methods prepare gemologists for making evaluations with minimal time, tools, and references. This step-by-step guide covers...
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Clarity Grading Diamonds
Mastering clarity grading diamonds takes a lot of experience. This grading guide, with definitions, images, and examples, can help beginning...
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Color Grading White Diamonds
Mastering the art of color grading white diamonds is a challenge. Learn about the standards, terms, tools, and testing procedures...
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Diamond Look-alike Comparison Chart
Distinguishing a diamond look-alike from the real thing can challenge new gemologists. However, specific gravity and birefringence hold the key...
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Prong Setting Gems: A Beginner’s Guide
Using prongs is the most common way to secure a gem to a jewelry piece. Learn basic prong setting procedures...
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Choosing the Right Jewelry Settings for Your Gems
How do you choose jewelry settings for your gems? Learn the pros and cons of pre-made settings, assembling findings, modifying...
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Clarity Grading for Colored Gemstones
Don't underestimate the importance of clarity, one of the Four Cs of gemstone grading. For faceted gems, basic clarity grading...
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Evaluating Gem Color: Hue, Tone, and Saturation
Accurately describing gem color is critical to determining a gemstone's value. Learn how to grade hue, tone, and saturation and...
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How To Correct Faceting Mistakes
We faceters all like to take pride in our work. However, no matter our skill level, we all make errors....
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Custom Gem Faceting Styles
Gem cutters can choose from many faceting styles. Learn about the most common custom cutting techniques and pick one that...
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Jewelry Nomenclature: Gem Settings
Jewelry designers and consumers can pick from many different gem settings. Learn the names and uses of common and speciality...
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Tips for Cutting Kunzite
Cutting kunzite and other gemstones with easy cleavage is challenging. These tips can help you facet this beautiful and valuable...
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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...
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Cutting Star and Cat’s Eye Gems
Learn how to cut star and cat's eye gems. Once you understand how these light effects work, you'll find unexpected...
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Simple Design Ideas For Freeform Gems
You can learn gem carving by practicing simple designs. Let the native shapes of stones inspire freeform gems you can...
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Advanced Cutting Techniques For Cabochons
Leftover gemstone rough is a great material for learning to cut cabochons. Learn advanced cabbing techniques and find new inspiration...
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Writing Effective Advertising for Gems and Jewelry
Follow these simple formulas for effective advertising. Engage your customers and translate the features of your gems and jewelry into...
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The Art and Science of Identifying Gemstones
Learn how to identify gems using gemology tools and the Gemology Tools software, which makes it easier than ever to...
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Opal Buying Guide
Our opal buying guide can help you learn how opals are graded, what to avoid, and how to identify a...
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An Introduction to Jewelry and Metalsmithing Tools
Manufacturing jewelry is a great way to tap into your creative side along with having something cool and original to...
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Australian Opals
Australian opals account for 95% of the world’s supply. Learn about Australia’s geological history, the start of its opal trade,...
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Shattuckite Value, Price, and Jewelry Information
Shattuckite is often mixed with quartz, and data often reported for properties may be erroneous. The cabochons are rich blue...
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Product Review, Opal Smart Chart
The newest thing in the opal world is the Opal Smart Chart. This is a software package designed to help...
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Spodumene Value, Price, and Jewelry Information
Extraordinarily difficult to cut, spodumene has several colorful varieties, such as hiddenite and kunzite, highly coveted for jewelry.
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Product Comparison, Polariscopes
Polariscopes are one of our most useful instruments. They come in a wide variety of prices and qualities. There are...
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Product Review, GemPro 50, Digital Scale
The least expensive digital scale for gem use is now the GemPro 50. It sells for around $150, which is...
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Product Review, Sony Cyber-shot
A Product Review on Sony Cyber-shot. Overall, it is an excellent camera and I was surprised by the low cost.The...
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Product Review, Opal The Smart Chart
The newest thing in the opal world is the Opal Smart Chart. This is a software package designed to help...
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Product Review, Diamond Calculator
There is a new piece of software available that will be of interest to many of you. It is called...
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Destructive Gemstone Testing
Destructive gemstone testing, done carefully, can help gemologists with difficult gem identifications. Learn the right techniques with our 5-part series....
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Living With Your Faceting Machine
One serious pitfall for the novice is the quality of advice they get in choosing what faceting machine to buy....
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Polishing Laps and Techniques
Polishing Laps and Techniques. Covers helpful information, tips, suggestions for polishing. A guide on techniques that will be useful for...
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Faceting Machine Survey
Recently, a survey was taken to see what kind of Facet Machines are being used by members of the Faceter's...
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Australian International Faceting Challenge 2000
The Australian International Faceting Challenge is a competition to see a cutters ability to cut a perfect stone. With designs...
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Identifying Inclusions Found in Synthetic Gems
Successful tips and guide in identifying Inclusions Found in Synthetic Gems. Read and learn several ways to identify inclusions found...
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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...
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An Introduction to Jewelry and Metalsmithing Tools
Guide to jewelry metalsmithing tools. Tips for choosing the right tools to get stared in jewelry metalsmithing.
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How to Make a Beaded Necklace
An overview on How to Make a Beaded Necklace. Detailed information on the tools, materials, designs and techniques on making...
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How Rare is That Gem?
Rarity is one of the most prized qualities of gemstones. But some gems are far more rare than others! This...
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Finding a job in the gem or jewelry business
This is a quick story about finding employment (a job) in the gem or jewelry industry. It explains why starting...
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Test Taking Tips and Strategies
Learn these quick and simple test taking tips and strategies to help you on your next gemology test.
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