Mercury (California, USA) 2 : 無料・フリー素材/写真
Mercury (California, USA) 2 / 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 | Mercury from California, USA. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA)A mineral is a naturally-occurring, solid, inorganic, crystalline substance having a fairly definite chemical composition and having fairly definite physical properties. At its simplest, a mineral is a naturally-occurring solid chemical. Currently, there are over 4900 named and described minerals - about 200 of them are common and about 20 of them are very common. Mineral classification is based on anion chemistry. Major categories of minerals are: elements, sulfides, oxides, halides, carbonates, sulfates, phosphates, and silicates.Elements are fundamental substances of matter - matter that is composed of the same types of atoms. At present, 118 elements are known (four of them are still unnamed). Of these, 98 occur naturally on Earth (hydrogen to californium). Most of these occur in rocks & minerals, although some occur in very small, trace amounts. Only some elements occur in their native elemental state as minerals. To find a native element in nature, it must be relatively non-reactive and there must be some concentration process. Metallic, semimetallic (metalloid), and nonmetallic elements are known in their native state.Mercury (Hg) is a metal that is liquid at Earth surface conditions. Because it is not solid or crystalline, it is not a mineral - technically, it is a mineraloid (as is opal, which is solid, but not crystalline). Mercury has a metallic luster, a silvery-gray color, and is significantly heavy for its size (high specific gravity). |
| 撮影日 | 2010-07-25 14:42:07 |
| 撮影者 | James St. John |
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