Geology of Gems by Eugenii Kievlenko

Edited by Dr. Art Soregaroli. First English Edition. Ocean Pictures Ltd., 2003 468 pages, including color supplementary - 32 pages. 136 color plates, 128 b/w drawings, hard cover

Preface:

Russian and former USSR geologists, mineralogists and other researchers have provided perhaps the most comprehensive studies of gemstone deposits and gemstone-bearing areas than those in any other part of the world. Documentations of these studies have reached other countries in somewhat piecemeal fashion. Geology of Gems provides for the first time in English a more complete review of the results of their work and an understanding of their considerations and conclusions on the genesis of such deposits.

The strength of the book lies the geologic-genetic approach to gemstone deposits throughout the world. Coverage is international in scope and includes most of the major gemstone deposits, albeit there is a heavy emphasis on deposits in the Russian Federation and former USSR. Although many important gemstone deposits have been discovered since the Geology of Gems was written, there has been no attempt to incorporate data on these deposits.

The author’s purpose in writing the book was to provide a framework for the exploration and discovery of new gemstone deposits. This goal has been accomplished. Eighteen chapters are devoted to specific minerals or mineral groups, such as Corundum, Beryl, Garnet, Charoite, etc. Unfortunately the book lacks a chapter on Diamonds, which have always received special and isolated attention in Russia.

Kievlenko’s classification of gemstones based on value (early 1990 prices) is the continuation of a Russian tradition dating from the mid-1880’s. Many gemologists, mineralogists and others will consider such a classification arbitrary and controversial, however, the classification provides insight into the history of Russian gemstone studies and does not detract from the geologic-genetic strength of the framework of the book.

There is considerable confusion in the literature with regards to deposit and geographic names and locations, especially where they have been translated into Russian and then into English. Partial resolution of this confusion was accomplished through consultation of various general reference and text books; inventories of mineral localities; geographic atlases and maps; various periodical journals devoted to gems, minerals and related topics; glossaries of obsolete mineral names and synonyms; personal conversations with learned friends; and communications with Michael Leybov and Ludmilla Cheshko (Egorova). This process considerably extended the editorial process and required some arbitrary selections. Thus, there is no inference that all names have been resolved. I have assumed that those citations in the text, which are not found in the References, are personal communications.

Brief and frank discussions with Wendell Wilson, John White and Bob Cook provided insight into dealing more directly with some issues. Their input is appreciated. I am especially grateful to my wife, Rosalie, for encouragement during her many months of solitude while editing was in progress, Carla Soregaroli for her many, many hours of word processing of several versions of the text, and Felix Kaminsky for his help in understanding Russian terminology and reinterpretation of some text.

Art Soregaroli Editor, English Edition

FORWARD TO THE ENGLISH EDITION	11
ACKNOWLEDGEMENTS	12
FOREWORD	13
1. GENERAL DATA ON GEMS	14
1.1. Classification of Gems	14
1.2. Jewels	18
1.3. Jewelry-Industrial and Industrial Stone	32
1.4. Synthetic Crystals – Substitutes of Natural Gems	33
2. CORUNDUM (RUBY AND SAPPHIRE)	38
2.1. Genera	38
2.2. Geological Genetic Types of Deposits	42
2.2.1. Magmatic Deposits	42
Basalt and Alkaline Basalt Extrusions	43
Alkaline Basic Lamprophyres	46
2.2.2. Pegmatite Deposits (Syenite Pegmatites)	48
2.2.3. Contact Metasomatic Deposits	49
Endoskarns in Marbles and Calciphyres	49
Micaceous Anorthosites in Mafic and Ultramafic Rocks	57
2.2.4. Metamorphic Deposits	61
2.2.5. Placer Deposits	61
3. BERYL	71
3.1. General	71
3.2. Emerald	73
3.2.1. General	73
3.2.2. Geological Genetic Types of Deposits	77
3.2.2.1. Pegmatite Deposits	77
3.3.2.2. Greisen Deposits	79
Ultramafic Greisens	80
Carbonate-Black Shale Greisens	95
3.2.2.3. Hydrothermal Deposits	96
3.2.2.4. Placer Deposits	102
3.3. Aquamarine and Other Jewelry Beryls	102
3.3.1. General	102
3.3.2. Geological Genetic Types of Deposits	105
3.3.2.1. Pegmatite Deposits	105
Miarolitic Granite Pegmatites	105
Microcline Beryl-Muscovite Vugless Pegmatites	114
3.3.2.2. Greisen Deposits	114
3.3.2.3. Post-Volcanic Exhalative-Hydrothermal Deposits	118
3.3.2.4. Placer Deposits	119
4. PRECIOUS OPAL	120
4.1. General	120
4.2. Geological Genetic Types of Deposits	124
4.2.1. Hydrothermal Post-Volcanic Deposits	124
4.2.2. Supergene Deposits	128
5. TOPAZ	132
5.1. General	132
5.2. Geological Genetic Types of Deposits	135
5.2.1. Pegmatite Deposits	135
5.2.2. Greisen Deposits	145
5.2.3. Hydrothermal Deposits	145
Post-Intrusive Plutonogenic Deposits	145
Post-Volcanic Exhalation Hydrothermal Deposits	147
5.2.4. Placer Deposits	149
6. TOURMALINE	151
6.1. General	151
6.2. Geological Genetic Types of Deposits	154
6.2.1. Pegmatite Deposits	154
6.2.2. Contact Metasomatic Deposits	171
6.2.3. Metamorphic Deposits	172
6.2.4. Placer Deposits	172
7. SPINEL	173
7.1. General	173
7.2. Geological Genetic Types of Deposits	175
7.2.1. Magnesian Skarn Deposits	175
7.2.2. Placer Deposits	180
8. GARNET	181
8.1. General	181
8.2. Geological Genetic Types of Deposits	186
8.2.1. Magmatic Deposits	186
Kimberlites	186
Basaltic Eruptive Breccias	191
Felsic and Intermediate Extrusive Rocks	193
8.2.2. Pegmatite Deposits	194
8.2.3. Contact Metasomatic Deposits	195
Exo- and Endoskarns	195
Apogabbro Metasomatites	196
8.2.4. Hydrothermal Deposits	198
Plutonic Deposits in Ultramafic Rocks	199
Post-Volcanic Deposits in Acid Extrusions	202
8.2.5. Metamorphic Deposits	202
8.2.6. Placer Deposits	204
9. PERIDOT (CHRYSOLITE)	208
9.1. General	208
9.2. Geological Genetic Types of Deposits	209
9.2.1. Magmatic Deposits	209
Kimberlites	210
Basalts and Alkaline Basaltoids	212
9.2.2. Hydrothermal deposit	215
Ultramafic Alkaline Massifs of the Central Type	215
Ultramafic Massifs of the Alpine Type	218
9.2.3. Placer Deposits	219
10. AMETHYST	221
10.1. General	221
10.2. Geological Genetic Types of Deposits	223
10.2.1. Pegmatite Deposits	223
10.2.2. Iron-Ore Skarn Deposits	225
10.2.3. Hydrothermal Deposits	226
Plutonogenic Deposits	226
Volcanogenic Deposits	233
Telethermal Deposits	236
10.2.4. Placer Deposits	236
11. TURQUOISE	237
11.1. General	237
11.2. Geological Genetic Types of Deposits	240
11.2.1. Deposits in Magmatic Rocks	240
11.2.2. Deposits in Sandy-Shale Rocks	250
12. AMBER	255
12.1. General	255
12.2. Geological Genetic Types of Deposits	261
12.2.1. Biogenic-Sedimentary Deposits	261
12.2.2. Placer Deposits	262
13. LAZURITE	273
13.1. General	273
13.2. Geological Genetic Types of Deposits	276
13.2.1. Deposits in Magnesian Skarns	276
13.2.2. Placer Deposits	287
14. JADEITE	288
14.1. General	288
14.2. Geological Genetic Types of Deposits	291
14.2.1. Contact Metasomatic Deposits in Ultramafic Rocks	291
14.2.2. Placer Deposits	302
15. NEPHRITE	303
15.1. General	303
15.2. Geological Genetic Types of Deposits	306
15.2.1. Contact Metasomatic Deposits	306
Deposits in Serpentinized Ultramafic Rocks	307
Deposits in Magnesian Skarns	319
15.2.2. Placer Deposits	323
16. CHAROITE	326
16.1 General	326
16.2 Geology and Genesis of the Sirenevyi Kamen Deposit	327
17. MALACHITE	333
17.1. General	333
17.2. Geological Genetic Types of Deposits	335
17.2.1. Deposits in Oxidized Zones of Copper Sulfide Ores in Carbonate-bearing Rocks	335
17.2.2. Placer Deposits	343
18. CHALCEDONY	345
18.1. General	345
18.1.1. Agate	347
18.1.2. Carneol, Carnelian, and Sard	350
18.1.3. Chrysoprase	351
18.1.4. Other Decorative Varieties	353
18.2. Geological Genetic Types of Deposits	355
18.2.1. Postvolcanic Hydrothermal Deposits	355
Chalcedony deposits in basic and intermediate volcanogenic rocks	355
Agate deposits in silicic volcanogenic rocks	367
18.2.2. Diagenetic and Catagenic Deposits	370
18.2.3. Deposits in Weathered Crusts	373
Chrysoprase deposits in nickel-bearing weathered crusts on ultramafic rocks	373
Eluvial and eluvial-diluvial placers	377
18.2.4. Placer Deposits	377
Agate-bearing conglomerates	378
Alluvial placer deposits	379
Shoreline placers	383
19. RHODONITE	383
19.1. General	383
19.2. Geological Genetic Types of Deposits	386
19.2.1. Deposits in Calcic Skarns	386
19.2.2. Hydrothermal Deposits	388
19.2.3. Metamorphic Deposits	389
19.2.4. Placer Deposits	398
20. ECONOMIC-GEOLOGICAL TYPES OF GEMSTONE DEPOSITS AND THE PRINCIPAL REGULARITIES IN THEIR SPATIAL DISTRIBUTION	400
Magmatic deposits	401
Pegmatites	401
Gemstone deposits in ultramafic Rocks	406
Gemstone deposits in ultramafic Rocks	407
Hydrothermal deposits	408
Metamorphogenic deposits	408
Weathered crusts	408
Placer deposits	409
ABBREVIATIONS	414
REFERENCE	415