| 书目名称 | Gemstones and Their Origins | | 编辑 | Peter C. Keller | | 视频video | | | 图书封面 |  | | 描述 | Each gem deposit-whether of primary origin in the parent rocks; or secondary as alluvial placers in valley floors, river gravels, or the sand of oceanic shelves presents an eloquent chronicle of the Earth‘s life story. It reveals to the expert the prodigious processes which formed the present crust of our planet, of which this volume discloses a small but exciting detail. The materials of the Earth‘s crust are the rocks. In this book, the author expounds on how they were formed, why they altered, why they became the cradles of precious gemstones, how they are categorized, and how they are now exploited by man. What initiates the growth of gemstones? How do they crystallize? Why do gemstones of the same species, originating from different sources, vary? What causes the occurrence of varieties? Why do diamonds, unlike other precious stones, occur not near the Earth‘s surface in its crust, but deep down beneath it in the upper mantle? These are only a few of the entrancing subjects discussed in this enlightening volume. The reader learns that the Earth is surprisingly alive and altering constantly-sometimes through slow and equable changes and at times by violent and tremendous catac | | 出版日期 | Book 1990 | | 关键词 | Pegmatit; growth; metamorphism; ocean; oceanic; water; mineral resources | | 版次 | 1 | | doi | https://doi.org/10.1007/978-1-4684-6674-4 | | isbn_softcover | 978-1-4684-6676-8 | | isbn_ebook | 978-1-4684-6674-4 | | copyright | Springer Science+Business Media New York 1990 |
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发表于 2025-3-21 19:30:57
