Gold (Element # 79) : 無料・フリー素材/写真
Gold (Element # 79) / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Gold (Au) is # 79 on the Periodic Table of Elements. Elemental gold is rare and valuable, principally because it is the only metal with a highly-attractive, deep, rich, yellowish color. It is the best example of a precious metal, or "noble metal". Native gold is the most common Au-bearing mineral. It occurs in some placer deposits and in some hydrothermal veins (often quartz-gold veins). "Gold nuggets" refers to gold masses in placers - they range in size from "gold dust" to boulders. Many minable gold deposits have invisible, microscopic gold only. Famous gold mining areas include the Homestake Mine (Black Hills, South Dakota, USA), the Red Lake Mine (Ontario, Canada), and the Witwatersrand Supergroup (South Africa).Forty-one isotopes of gold are known. Only one occurs naturally - gold-197.-----------------------------Info. at:en.wikipedia.org/wiki/Goldanden.wikipedia.org/wiki/Isotopes_of_goldandwww.flickr.com/photos/jsjgeology/albums/72157651325153769andwww.flickr.com/photos/jsjgeology/collections/721576458473... |
| 撮影日 | 2024-09-28 12:42:19 |
| 撮影者 | James St. John |
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