Arsenic (Andreasberg, Harz Mountains, Germany) 1 : 無料・フリー素材/写真
Arsenic (Andreasberg, Harz Mountains, Germany) 1 / 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 | Arsenic from Germany. (3.0 cm across at its widest)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 as minerals.Arsenic is one of the semimetals/metalloids. It has a metallic luster and bright silvery gray color on freshly broken surfaces. Weathered, tarnished surfaces have a very dull metallic to nonmetallic luster and dark gray color. Arsenic has a gray streak, no cleavage, and is moderately soft (H = 3.5). Like all semimetals/metalloids, arsenic is not malleable - it breaks along fractures.Locality: Andreasberg, Harz Mountains, Germany |
| 撮影日 | 2015-05-10 22:27:06 |
| 撮影者 | James St. John |
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