Gemstone Buying Guide

How to Evaluate, Identify, Select & Care For Colored Gems





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Tips on Judging Colored Gems

This updated full-color guide to colored gems provides concise yet comprehensive information on quality evaluation, price comparison, gem identification, cutting styles, treatments, fake stones, optical effects, gem care and geographic sources. Many of the gems are shown mounted in striking designer jewelry. There are 323 new color photos and several new gem species and varieties in this new Third Edition. Also included are interesting historical facts mixed with scientific data and a bit of folklore. Written for consumers and professionals, the Gemstone Buying Guide is a practical, well-illustrated resource for buying, identifying and caring for colored gems. If you want to become a savvy buyer and learn how to select colored gemstones, then you’ll find the Gemstone Buying Guide a fascinating and valuable resource.

356 color photos / 156 pages / paperback

$19.95 / ISBN 978-0-929975-51-1 / 7" x  9" (18 x 23 cm)

International Jewelry Publications

Click here to buy the Gemstone Buying Guide Now


For information on a companion guide, Rare Gemstones, click here.


Table of Contents

Acknowledgments 5                                                                                                                                                                     

1     Colored Gem Price Factors in a Nutshell 7                                                                        

       Price Factors Explained 7

       Two Common Beliefs Which Warrant Review 15

       Colored Gem Pricing 16


2     Shape & Cutting Style 17

       Gemstone Terms Defined 18

       Traditional Cutting Styles 19

       Non-traditional Cuts 22 

       Carving 24

       Drusy Gem Materials 28

       Trapiche Stones 29


3     Carat Weight 30

       Size Versus Carat Weight 30                                                                                                                                                     

       Effect of Carat Weight on Price 31

       Estimating Carat Weight 32


4     Gemstone Color 33                                                                                                                                                                    

       Evaluating Gemstone Color 35 

       How to Examine Color 35    

       How Lighting Affects Gem Color 37 


5      Judging Clarity & Transparency 38

        Transparency 39

        Gemstone Inclusions 40

        Gemstone Blemishes 42 

        Examining Gemstones for Clarity 42

        How Lighting Can Affect Your Perception of Clarity 44

        Do We Need Grades to Evaluate Clarity and Transparency? 45


6      Judging Cut Quality 46

        Judging the Face-Up View 46

        Judging the Profile 48


7      Evaluating Star & Cat’s-Eye Stones 51


8      Treatments & Processes 54


9.     Synthetic Stones 58

        Synthetic Versus Natural 58 


10   Deceptive Practices 60

        Misnomers 62

11   Gemstone Descriptions 63

       Amethyst and Other Quartz Stones 66 

       Chalcedony 70   

       Chrysoberyl (Alexandrite, Cat’s-eye) 74

       Emerald and Other Beryl Stones 76 

       Garnet 80 

       Iolite 85 

       Jade 86 

       Lapis Lazuli 94

       Malachite 95

       Moonstone and Some Other Feldspars 96

       Opal 98

       Peridot 106  

       Spodumene 107  

       Ruby & Sapphire (Corundum) 108

       Spinel 112 

       Tanzanite and Other Zoisites 114 

       Topaz 116

       Tourmaline 118

       Turquoise 122

       Zircon 124

       Lesser-known gemstones

        Ammolite 126 

        Andalusite, Apatite 127  

        Azurite, Benitoite 128

        Calcite, Charoite 129

        Danburite, Diaspore 130

        Diopside, Fluorite 131 

        Gaspeite, Hematite 132

        Kyanite, Larimar 133

        Maw-sit-sit, Natural Glass (Obsidian, Moldavite) 134 

        Phenakite, Prehnite 135

        Psilomelane, Rhodochrosite 136

        Rhodonite, Seraphinite 137

        Serpentine, Sodalite 138

        Sphalerite, Sphene (Titanite) 139

        Sugilite, Vesuvianite 140

12   Caring for Your Gems 141  

Birthstones & Anniversary Stones 144                                                                                              

Gemstones in Order of Descending Mohs Hardness 145

Gemstones in Order of Descending Refractive Index 146

Gemstones in Order of Descending Specific Gravity 147

Bibliography 148

Index 151


Reviews of the Second Edition

"Far more than a buying guide, it is one of the finest collections of gem photographs I’ve ever seen. The book is a delight for family and guests when laid on your coffee table...The amount of work in this book is to be believed only by holding it in your hands. If you see the book, you will probably purchase it on the spot."

Anglic Gemcutter

"An excellent book for the photographs alone, but such a concise way to inform the reader of the many aspects of gemmology and jewellery buying is superb. In an easy-to-read format, Renée Newman has been able to capture the fundamentals of buying coloured gemstones, including jade, opal, topaz, garnet, ruby spinel, chalcedony and tourmaline. The book is illustrated with excellent color photographs, gemstone description charts, and information on evaluating colour and transparency.

    The author advises in detail on the majority of gems available to the consumer, including research material on treatments, synthetic stones and styles of cuts. The book discusses prices for each of the gems outlined, as well as quality, evaluation, cleaning and care.

    I found this book a pleasure to read and to look at, and have referred back to it many times to verify my own experiences. I recommend this book to all lay people who want to buy gemstones and to gemmologists who need to be reminded of the importance of the buying process–something which we sometimes take for granted."

Canadian Gemmologist

"Comprehensive, factual and well-presented...Particularly noteworthy in this book are the quality colour photographs that have been carefully chosen to illustrate the text. This is a quality buying guide that is recommended for purchase to consumers, gemologists, and students of gemmology—irrespective of their standard of knowledge of gemmology"

Australian Gemmologist

"Certainly successful. It is worth having for both novices and more experiences lapidaries and gem buyers. Novices will be able to learn enough to keep from making costly mistakes, while the more experienced gem buyers and lapidaries can use it for reference...

    Newman discusses important topics such as how to judge phenomenal stones, discern deceptive practices and differentiate between various treatments. These aspects are well-covered in the text and are accompanied by excellent color photographs, charts, tables, line drawings and graphs.

    Newman’s well-illustrated chapter on shape and cut is particularly useful to students and new buyers of gems since it introduces all the outstanding new cuts that might puzzle cautious buyers.

    Readers will learn about color grading, how light affects color, and how color affects the price of gemstones. The chapter on treatments includes filling, impregnation, coating, diffusion and dyeing. Heat treating and irradiation are also discussed along with a list of stones commonly enhanced by irradiation techniques.

    The last part of the book has descriptions of gem species and varieties, again with excellent illustrations. Prospective customers learn about hardness, toughness, density, refraction, pleochroism and reaction to heat and chemicals."

Lapidary Journal

"Concise, up-to-date and accompanied by very fine photographs...With colour on almost every opening, few could resist this book whether or not they were in the gemstone and jewelry trade or were gemologists. Here the reader is given all the information needed to show the customer what a stone is, interesting facts about particular species and advice on cleaning and conservation. Some properties have to be given but they are introduced before the stones are described. Since this is not a gem testing book but an introduction to appraising gemstones, we are shown how to evaluate cuts, styles, color, inclusions –all with a view to establishing a specimen within an acceptable order of value as far as is possible. Treatments, phenomenal stones and synthetic stones are also described."

A great book.

Journal of Gemmology


Buy The Gemstone Buying Guide

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