Uraninite (Cardiff Mine, Wilberforce, Ontario, Canada) : 無料・フリー素材/写真
Uraninite (Cardiff Mine, Wilberforce, Ontario, Canada) / 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 | Uraninite from Ontario, Canada. (Robert Lauf collection)Large, black crystal near the lower right = uraniniteGreenish crystal near the upper left = probably apatiteA 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.The oxide minerals all contain one or more oxide anions (O-2). The oxide minerals include species that are hydroxy-oxides. The hydroxide minerals (those with one or more OH-) are usually considered together with the oxides. Many sulfide minerals are not stable in Earth-surface conditions. In the presence of oxygen and moisture, sulfide minerals tend to tarnish or alter to oxides and hydroxy-oxides. All except the most inert elements (such as the platinum-group elements and gold and noble gases) readily form oxides. Gold oxide forms only under special conditions.Uraninite is a scarce uranium oxide mineral, UO2. Uranium is a radioactive element and uraninite is a primary uranium mineral. It forms under non-oxidizing conditions - in such environments, the uranium is in the form of U+4 ions. In an oxidizing environment, such as the Earth's surface, uraninite alters to secondary uranium minerals having U+6 ions, which are usually incorporated into uranyl ions, (UO2)+2.Uraninite is black, moderately hard, and radioactive. It occurs in some pegmatites, in some hydrothermal veins, and in some sedimentary rocks.Locality: Cardiff Mine, Wilberforce, southeastern Ontario, southeastern Canada---------------Photo gallery of uraninite:www.mindat.org/gallery.php?min=4102 |
| 撮影日 | 2016-04-30 13:45:42 |
| 撮影者 | James St. John |
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