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