<p>Preface xi</p> <p>Acknowledgements xiii</p> <p><b>Part I Developing Base Knowledge </b><b>1</b></p> <p><b>1 Minerals and Mineralogy </b><b>3</b></p> <p>1.1 Minerals and Rocks 3</p> <p>1.2 What is a Gemstone? 3</p> <p>1.3 Atoms, Elements, and Bonding 4</p> <p>1.3.1 Protons, Neutrons, and Electrons 4</p> <p>1.3.2 Atomic Mass 5</p> <p>1.3.3 Atomic Structure, Electrical Charges, and Ions 5</p> <p>1.3.4 Elements 6</p> <p>1.3.5 Element Groups 6</p> <p>1.3.6 Elemental Abundance in the Earth’s Crust 7</p> <p>1.3.7 Compounds and Mixtures 8</p> <p>1.3.8 Chemical Bonds 8</p> <p>1.4 Physical Properties of Minerals 9</p> <p>References 11</p> <p><b>2 Basics of Rocks and Geology </b><b>13</b></p> <p>2.1 Earth System Science 13</p> <p>2.2 The Earth’s Structure and Plate Tectonics 13</p> <p>2.3 General Rock Types and the Rock Cycle 19</p> <p>2.4 Metasomatism and Hydrothermal Fluids 23</p> <p>2.5 Geological Structures 24</p> <p>2.6 Important Rock Types for Gemstone Deposits 24</p> <p>2.7 Weathering, Sedimentation, and Secondary Gem Deposits 26</p> <p>References 28</p> <p><b>3 Intermediate Mineralogy </b><b>29</b></p> <p>3.1 Structure and Chemistry of Minerals 29</p> <p>3.1.1 Crystallography and Symmetry 29</p> <p>3.1.2 Mineral Classes 32</p> <p>3.1.3 Mineral Formulae 32</p> <p>3.1.4 Element Substitutions 33</p> <p>3.2 Light 34</p> <p>3.2.1 Reflection and Refraction 34</p> <p>3.2.2 Illumination 39</p> <p>3.2.3 Dispersion 41</p> <p>3.2.4 Optic Class 42</p> <p>3.2.5 Color in Minerals 43</p> <p>3.2.6 Pleochroism 44</p> <p>3.2.7 Transparency 46</p> <p>References 47</p> <p><b>4 Concepts of Gemmology and Tools </b><b>49</b></p> <p>4.1 Concepts of Gemmology 49</p> <p>4.1.1 Gemmological Properties for Testing, Faceting, and Treatments 49</p> <p>4.2 Tools 51</p> <p>4.2.1 Collecting and Field Tools 51</p> <p>4.2.2 Gemmological Tools 52</p> <p>4.2.3 Advanced Tools 57</p> <p>References 60</p> <p><b>Part II Gemstones and Their Origins </b><b>63</b></p> <p><b>5 Diamond </b><b>65</b></p> <p>5.1 Introduction 65</p> <p>5.2 Basic Qualities of Diamond 67</p> <p>5.2.1 Crystal Structure 68</p> <p>5.2.2 Crystal Chemistry and Type Classification of Diamond 69</p> <p>5.2.3 Diamond Crystal Forms 71</p> <p>5.2.4 Colored Diamonds 74</p> <p>5.3 Common Diamond Treatments 76</p> <p>5.4 Synthetic Diamond 79</p> <p>5.5 Geology of Diamond and Kimberlite 79</p> <p>5.5.1 Diamond Growth 81</p> <p>5.5.2 Kimberlite Volcanoes 82</p> <p>5.5.3 Lamproite 83</p> <p>5.6 Global Distribution and Production of Diamond 84</p> <p>5.7 Diamonds from Canada 92</p> <p>5.8 The 4 Cs 95</p> <p>5.8.1 Cut 95</p> <p>5.8.2 Clarity 95</p> <p>5.8.3 Color 96</p> <p>5.8.4 Carat 98</p> <p>5.9 Diamond Shapes 98</p> <p>5.10 Diamond Valuation 99</p> <p>5.11 Kimberley Process: A 5th C? 100</p> <p>References 100</p> <p><b>6 Corundum </b><b>103</b></p> <p>6.1 Introduction 103</p> <p>6.2 Basic Qualities of Corundum 104</p> <p>6.2.1 Chemistry and Crystal Structure of Corundum 104</p> <p>6.2.2 Corundum Crystal Forms 104</p> <p>6.2.3 Colors of Corundum 104</p> <p>6.3 Faceted Gem Corundum 107</p> <p>6.4 Corundum Valuation 107</p> <p>6.5 Corundum Treatments, Synthetics, and Imitations 110</p> <p>6.6 Geology of Gem Corundum: Three Main Genetic Models 113</p> <p>6.6.1 Metamorphic Corundum in Silica-Deficient Gneisses, Mafic-Ultramafic Rocks and Marbles 114</p> <p>6.6.2 Xenocrysts in Alkali Basalts and Lamprophyres 118</p> <p>6.6.3 Secondary Accumulation in Placers 120</p> <p>6.7 Rarity of Gem Corundum 124</p> <p>6.8 Global Distribution and Production of Corundum 124</p> <p>References 127</p> <p><b>7 Beryl </b><b>131</b></p> <p>7.1 Introduction 131</p> <p>7.2 Basic Qualities of Beryl 132</p> <p>7.2.1 Chemistry and Crystal Structure of Beryl 132</p> <p>7.2.2 Colors of Beryl and Gem Varieties 134</p> <p>7.3 Beryl Valuation 138</p> <p>7.4 Common Treatments, Synthetics, and Imitations 140</p> <p>7.5 Geology of Gem Beryl: Three Main Genetic Models 141</p> <p>7.5.1 Pegmatitic 141</p> <p>7.5.2 Magmatic 141</p> <p>7.5.3 Metamorphic 146</p> <p>7.6 Large Beryl Crystals 149</p> <p>7.7 Global Distribution of Beryl 149</p> <p>References 150</p> <p><b>8 Pegmatites </b><b>153</b></p> <p>8.1 Introduction 153</p> <p>8.2 Pegmatite Mineralogy 153</p> <p>8.3 Pegmatite Genesis 154</p> <p>8.4 Geochemical Families of Pegmatites 155</p> <p>8.5 Pegmatite Morphology 157</p> <p>8.6 Corrosion 161</p> <p>8.7 Rarity of Gem-Bearing Pegmatites 162</p> <p>8.8 Tourmaline 162</p> <p>8.8.1 Introduction and Basic Qualities of Tourmaline 162</p> <p>8.8.2 Chemistry and Crystal Structure of Tourmaline 165</p> <p>8.8.3 Colors and Gem Varieties of Tourmaline 166</p> <p>8.8.4 Tourmaline Recognition, Value and Treatments 168</p> <p>8.9 Spodumene 172</p> <p>8.9.1 Introduction and Basic Qualities of Spodumene 172</p> <p>8.9.2 Colors and Gem Varieties of Spodumene 173</p> <p>8.9.3 Spodumene Recognition, Value, and Treatments 173</p> <p>8.10 Topaz 175</p> <p>8.10.1 Introduction and Basic Qualities of Topaz 175</p> <p>8.10.2 Geology of Gem Topaz 176</p> <p>8.10.3 Colors and Gem Varieties of Topaz 179</p> <p>8.10.4 Topaz Recognition, Value, and Treatments 181</p> <p>References 181</p> <p><b>9 Chrysoberyl </b><b>185</b></p> <p>9.1 Introduction and Basic Qualities of Chrysoberyl 185</p> <p>9.2 Geology of Gem Chrysoberyl 185</p> <p>References 189</p> <p><b>10 Spinel </b><b>191</b></p> <p>10.1 Introduction and Basic Qualities of Spinel 191</p> <p>10.2 Geology of Gem Spinel 192</p> <p>References 195</p> <p><b>11 Tanzanite </b><b>197</b></p> <p>11.1 Introduction and Basic Qualities of Tanzanite 197</p> <p>11.2 Geology of Tanzanite 197</p> <p>References 200</p> <p><b>12 The Garnet Group </b><b>201</b></p> <p>12.1 Introduction and Basic Qualities of the Garnet Group 201</p> <p>12.2 Geology of Gem Garnet 201</p> <p>References 207</p> <p><b>13 Jade: Jadeite and Nephrite </b><b>209</b></p> <p>13.1 Introduction and Basic Qualities of Jade 209</p> <p>13.2 Geology of Jade 209</p> <p>References 217</p> <p><b>14 Quartz and Silica Gems </b><b>219</b></p> <p>14.1 Introduction and Basic Qualities of Quartz and Silica Gem Varieties 219</p> <p>14.2 Quartz 219</p> <p>14.3 Amethyst 220</p> <p>14.4 Agate 221</p> <p>14.5 Opal 222</p> <p>References 228</p> <p><b>15 Other Gems </b><b>231</b></p> <p>15.1 Olivine 231</p> <p>15.1.1 Introduction and Basic Qualities of Olivine 231</p> <p>15.1.2 Geology of Gem Peridot 231</p> <p>15.2 Turquoise 236</p> <p>15.2.1 Introduction and Basic Qualities of Turquoise 236</p> <p>15.2.2 Geology of Turquoise 237</p> <p>15.3 Lapis Lazuli 238</p> <p>15.3.1 Introduction and Basic Qualities of Lapis Lazuli 238</p> <p>15.3.2 Geology of Lapis Lazuli 238</p> <p>15.4 Zircon 243</p> <p>15.4.1 Introduction and Basic Qualities of Zircon 243</p> <p>15.4.2 Geology of Gem Zircon 244</p> <p>References 247</p> <p><b>16 Organic Gems </b><b>251</b></p> <p>16.1 Amber 251</p> <p>16.2 Ammolite 251</p> <p>References 257</p> <p>Index 259</p>