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Geology of Gems


English Edition

Eugenii Kievlenko (1923-2000) was a prominent Russian geologist with extensive experience in the exploration, discovery, and evaluation of mineral deposits of all kinds. He discovered dozens of gemstone deposits in various parts of Russia and has been credited with reviving the gemstone-cutting industry of the country.
Geology of Gems is the first comprehensive English language publication to place gem deposits into a concise geological and genetic framework which provides an understanding of existing deposits and the environments of their formation. The book is international in scope and covers most major gem deposits, although there is a strong emphasis on former USSR and Russian Federation deposits.
Eighteen chapters are devoted to specific gems (precious corundum, beryl, etc.). Each chapter contains historical and mineralogical data, with discussions regarding chromophores responsible for various varieties. Major gem deposits and districts are described for each country relative to a geological-genetic classification. The text is liberally illustrated with geological and geographic maps, sections (with scales) and other figures, as well as with numerous excellent color photographs.
Very few books have been written about the geology of gem deposits. Any person who wants to be a “gem hunter” will benefit from reading this book. It contains information that is found nowhere else. This English edition is an easy-to-read and geologically accurate translation.

Geology of GemsTable of Contents

Forward to the English Edition11
Acknowledgements12
Foreword13
1. General Data on Gems14
1.1 Classification of Gems14
1.2 Jewels18
1.3 Jewelry-Industrial and Industrial Stones32
1.4 Synthetic Crystals - Substitutes of Natural Gems33
2. Corundum (Ruby and Sapphire)38
2.1 General38
2.2 Geological Genetic Types of Deposits42
2.2.1 Magmatic Deposits42
Basalt and Alkaline Basalt Extrusions43
Alkaline Basic Lamprophyres46
2.2.2 Pegmatite Deposits (Syenite Pegmatites)48
2.2.3 Contact Metasomatic Deposits49
Endoskarns in Marbles and Calciphyres49
Micaceous Anorthosites in Mafic and Ultramafic Rocks57
2.2.4 Metamorphic Deposits61
2.2.5 Placer Deposits61
3. Beryl71
3.1 General71
3.2 Emerald73
3.2.1 General73
3.2.2 Geological Genetic Types of Deposits77
3.2.2.1 Pegmatite Deposits77
3.2.2.2 Greisen Deposits79
Ultramafic Greisens80
Carbonate-Black Shale Greisens95
3.2.2.3 Hydrothermal Deposits96
3.2.2.4 Placer Deposits102
3.3 Aquamarine and Other Jewelry Beryls102
3.3.1 General102
3.3.2 Geological Genetic Types of Deposits105
3.3.2.1 Pegmatite Deposits105
Miarolitic Granite Pegmatites105
Microcline-Beryl-Muscovite Vugless Pegmatites114
3.3.2.2 Greisen Deposits114
3.3.2.3 Post-Volcanic Exhalative-Hydrothermal Deposits118
3.3.2.4 Placer Deposits119
4. Precious Opal120
4.1 General120
4.2 Geological Genetic Types of Deposits124
4.2.1 Hydrothermal Post-Volcanic Deposits124
4.2.2 Supergene Deposits128
5. Topaz132
5.1 General132
5.2 Geological Genetic Types of Deposits135
5.2.1 Pegmatite Deposits135
5.2.2 Greisen Deposits145
5.2.3 Hydrothermal Deposits145
Post-Intrusive Plutonogenic Deposits145
Post-Volcanic Exhalation Hydrothermal Deposits147
5.2.4 Placer Deposits149
6. Tourmaline151
6.1 General151
6.2 Geological Genetic Types of Deposits154
6.2.1 Pegmatite Deposits154
6.2.2 Contact Metasomatic Deposits171
6.2.3 Metamorphic Deposits172
6.2.4 Placer Deposits172
7. Spinel173
7.1 General173
7.2 Geological Genetic Types of Deposits175
7.2.1 Magnesian Skarn Deposits175
7.2.2 Placer Deposits180
8. Garnet181
8.1 General181
8.2 Geological Genetic Types of Deposits186
8.2.1 Magmatic Deposits186
Kimberlites186
Basaltic Eruptive Breccias191
Felsic and Intermediate Extrusive Rocks193
8.2.2 Pegmatite Deposits194
8.2.3 Contact Metasomatic Deposits195
Exo- and Endoskarns195
Apogabbro Metasomatites196
8.2.4 Hydrothermal Deposits198
Plutonic Deposits in Ultramafic Rocks199
Post-Volcanic Deposits in Felsic Extrusions202
8.2.5 Metamorphic Deposits202
8.2.6 Placer Deposits204
9. Peridot (Chrysolite)208
9.1 General208
9.2 Geological Genetic Types of Deposits209
9.2.1 Magmatic Deposits209
Kimberlites210
Basalts and Alkaline Basaltoids212
9.2.2 Hydrothermal Deposits215
Ultramafic Alkaline Massifs of the Central Type215
Ultramafic Massifs of the Alpine Type218
9.2.3 Placer Deposits219
10. Amethyst221
10.1 General221
10.2 Geological Genetic Types of Deposits223
10.2.1 Pegmatite Deposits223
10.2.2 Iron-Ore Skarn Deposits225
10.2.3 Hydrothermal Deposits226
Plutonogenic Deposits226
Volcanogenic Deposits233
Telethermal Deposits236
10.2.4 Placer Deposits236
11. Turquoise237
11.1 General237
11.2 Geological Genetic Types of Deposits240
11.2.1 Deposits in Magmatic Rocks240
11.2.2 Deposits in Sandy-Shale Rocks250
12. Amber255
12.1 General255
12.2 Geological Genetic Types of Deposits261
12.2.1 Biogenic-Sedimentary Deposits261
12.2.2 Placer Deposits262
13. Lazurite273
13.1 General273
13.2 Geological Genetic Types of Deposits276
13.2.1 Deposits in Magnesian Skarns276
13.2.2 Placer Deposits287
14. Jadeite288
14.1 General288
14.2 Geological Genetic Types of Deposits291
14.2.1 Contact Metasomatic Deposits in Ultramafic Rocks291
14.2.2 Placer Deposits302
15. Nephrite303
15.1 General303
15.2 Geological Genetic Types of Deposits306
15.2.1 Contact Metasomatic Deposits306
Deposits in Serpentinized Ultramafic Rocks307
Deposits in Magnesian Skarns319
15.2.2 Placer Deposits323
16. Charoite326
16.1 General326
16.2 Geology and Genesis of the Sirenevy Kamen Deposit327
17. Malachite333
17.1 General333
17.2 Geological Genetic Types of Deposits335
17.2.1 Deposits in Oxidized Zones of Copper Sulfide Ores in Carbonate-bearing Rocks335
17.2.2 Placer Deposits343
18. Chalcedony345
18.1 General345
18.1.1 Agate347
18.1.2 Carneol, Carnelian, and Sard350
18.1.3 Chrysoprase351
18.1.4 Other Decorative Varieties353
18.2 Geological Genetic Types of Deposits355
18.2.1 Post-Volcanic Hydrothermal Deposits355
Chalcedony deposits in basic and intermediate volcanogenic rocks355
Agate deposits in silicic volcanogenic rocks367
18.2.2 Diagenetic and Catagenic Deposits370
18.2.3 Deposits in Weathered Crusts373
Chrysoprase deposits in nickel-bearing weathered crusts on ultramafic rocks373
Cacholong deposits in weathered crusts377
18.2.4 Placer Deposits377
Eluvial and eluvial-deluvial placer deposits377
Agate-bearing conglomerates378
Alluvial placer deposits379
Shoreline placer deposits382
19. Rhodonite383
19.1 General383
19.2 Geological Genetic Types of Deposits386
19.2.1 Deposits in Calcic Skarns386
19.2.2 Hydrothermal Deposits388
19.2.3 Metamorphic Deposits389
19.2.4 Placer Deposits398
20. Economic-Geological Types of Gemstone Deposits and the Principal Regularities in their Spatial Distribution400
Magmatic deposits401
Pegmatites401
Gemstone deposits in ultramafic rocks406
Magnesian skarns407
Hydrothermal deposits408
Metamorphogenic deposits408
Weathered crusts408
Placer deposits409
Abbreviations414
Reference415