Natural Gemstone
Natural Gemstones
作者：Geological Survey (U.S.)
体例：题 章数：22
字数：20,795 来源：Project Gutenberg
版本与结构
- 来源版本
- 本站收录 1 个来源：Project Gutenberg（20,795 字）。
- 分章依据
- 按「题」标记切分为 22 题（Gutenberg 卷册标记）。
- 篇幅分布
- 平均每题 945 字。
- 原文溯源
cache/epub/47999/pg47999.txt（Project Gutenberg）
章节目录
共 22 题- Natural gemstones
- Geologic environment
- Mineral gemstones
- According to Mohs’ scale, the hardness of—
- Colorless to faint yellowish tinge, also variable
- Jade (hardness: 6 Mohs)
- White, deep green, creamy brown
- Olive to lime green
- Wine yellow, pale blue, green, violet, or red
- Sky blue; greenish blue
- Birthstones
- Organic gemstones
- Buyer beware
- Gemstones: Value of U.S. production vs. imports, 1986 and 1989[1]
- Chemical formulas of gemstones
- Some ways to contact a local rock, mineral, or gem club
- Write to the—
- Role of the U.S. Geological Survey (USGS)
- Selected general references
- Acknowledgments
- Photographs
- Transcriber’s Notes