Exotic Gems, Volume 3: How to Identify, Evaluate, Select and Care For Matrix Opal, Fire Agate , Blue Chalcedony, Rubellite, Indicolite, Paraiba and Other Tourmalines

Exotic Gems, Volume 3: How to Identify, Evaluate, Select and Care For Matrix Opal, Fire Agate , Blue Chalcedony, Rubellite, Indicolite, Paraiba and Other Tourmalines

by Renée Newman




Exotic Gems, Volume 3 is the third in a series of books that explains with close-up photos the price factors and identifying traits of unusual gems. The stones are shown not only loose but also in jewelry, in the rough, under magnification and as beads in 422 color photos. Fun facts, historical anecdotes, geographic sources, gem treatment information, cutting advice, gemstone lighting recommendations, and tips on gem care are included along with diagrams and tables to aid in identification and evaluation. If you're interested in matrix opal, fire agate, blue chalcedony, Paraiba tourmaline, rubellite or other tourmalines, Exotic Gems can provide you with jewelry design ideas and in-depth information that will help you be a smart buyer and seller. Written in a succinct and user-friendly style, Exotic Gems: Volume 3 is an ideal reference for jewelers, sales associates, appraisers, gem collectors, gemology students, designers gem dealers and consumers.
Illustration Details: 422 color photos, plus diagrams, tables and charts

Product Details

ISBN-13: 9780929975481
Publisher: International Jewelry Publications
Publication date: 02/18/2014
Pages: 136
Product dimensions: 5.02(w) x 8.56(h) x 0.38(d)

Read an Excerpt

Residents of San Diego County, California may wonder why a gem such as tourmaline is featured in a book entitled Exotic Gems. Tons of it have been mined there, so it might be perceived as an ordinary gemstone. However, to China's Dowager Empress Tzu-Hsi (1835-1908), tourmaline was truly an exotic gem. Her love of the pink stone, which was unavailable in China, triggered San Diego's mining boom in the early 1900's. Pink tourmaline buttons and jewelry became a symbol of wealth and status among China's royalty, so buyers were sent to the California mines to select stones in order to meet the Chinese demand. After the Empress died in 1908, she was laid to rest in her tomb with her head on a pillow carved from pink tourmaline.

The term “exotic” has two definitions that apply to the gems in this book. According to the Merriam Webster Dictionary, “exotic” can refer to people, places or things that are:

1. of foreign origin; introduced from abroad

2. strikingly, excitingly or mysteriously different or unusual

Table of Contents

1. Exotic Gems 9

2. Price Factors in a Nutshell 12

Price Factors Explained 12

Color 12

Clarity 14

Transparency 17

Shape 18

Cutting Style 18

Cut Quality 18

Brilliance 19

Carat Weight or Stone Size 20

Treatment Status 20

Copper, Chromium and/or Vanadium Content 20

Geographic Origin 20

Distinctness of Optical Effects (Phenomena) 21

Colored Gem Pricing 22

3. Tourmaline Group 23

A Brief History of Tourmaline 23

What is Tourmaline? 27

Identifying Tourmaline 28

Tourmaline Chemistry 29

Tourmaline Species Characteristics in Brief 31

Tourmaline Varieties 33

How a Master Cutter Cuts a Tourmaline 34

Cutting Tourmaline (by John Bradshaw) 38

Caring for Tourmaline 38

4. Paraiba & Other Copper Tourmalines 39

What is a Paraiba Tourmaline? 42

Identification of Cuprian Tourmaline 45

Price Factors for Copper-Bearing Tourmaline 47

Alternative Terms for “Paraiba” 48

5. Blue to Green Tourmalines 49

What is Indicolite? 49

What is Chrome Tourmaline? 50

Verdelite or Green Tourmaline? 52

Blue-green Tourmaline 55

Gray Tourmaline 56

Identifying Green Tourmaline 57

6. Pink & Red Tourmaline 58

What is Rubellite? 60

Evaluating Pink & Red Tourmaline 63

Sources of Pink & Red Tourmaline 64

7. Yellow, Orange & Brown Tourmalines 66

8. Multicolored Tourmalines 70

Formation of Multicolored Tourmaline 72

Liddicoatite 73

Effect of Color Zoning on Pricing 74

Pleochroic Multicolor Effect 74

Multicolored Tourmaline Jewelry 75

9. Cat's-eye & Color-change Tourmaline 79

Color-change Tourmaline 81

10. Blue Chalcedony 86

What is Chalcedony? 88

Identifying Blue Chalcedony 90

Geographic Sources of Blue Chalcedony 91

Judging Blue Chalcedony Quality 97

Caring for Blue Chalcedony 98

11. Fire Agate 99

Fire Agate Price Factors 101

Cutting Fire Agate 104

Caring for Fire Agate 108

12. Matrix Opal 109

Boulder Matrix Opal 112

Andamooka Matrix Opal 120

Honduras Matrix Opal 122

Mexican Matrix Opal 124

Identifying Traits of Opal 125

Pricing and Evaluation of Matrix Opal 127

Caring for Matrix Opal 130

Bibliography 131

Index 134

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