Magnesite (Mesozoic; Premier Chemicals Mine, Paradise Range, Nevada, USA) 1 : 無料・フリー素材/写真
Magnesite (Mesozoic; Premier Chemicals Mine, Paradise Range, Nevada, USA) 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 | Massive, secondary magnesite from the Mesozoic of Nevada, USA. (~10.0 centimeters 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 6100 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.Magnesite is a magnesium carbonate mineral (MgCO3). It is the end member of a chemical continuum with dolomite (CaMg(CO3)2) and calcite (CaCO3). It often forms coarsely-crystalline masses or chalky / earthy masses. It has a nonmetallic luster and can be any color, but is often whitish. It has a white streak, a hardness of about 3.5 to 4.5, and rhombohedral cleavage. Magnesite is usually the result of metamorphic chemical alteration of Mg-bearing rocks such as peridotites and serpentinites by the action of carbonic acid-rich fluids.Seen here is a magnesium ore sample - this is rock-forming, very fine-grained magnesite from a mine in west-central Nevada. At the site, magnesite and brucite (Mg(OH)2) are mined for their magnesium content. The deposits are hosted by the Triassic-aged Luning Formation. Published research indicates that dolostones in the upper Luning Formation were hydrothermally altered to magnesite. Brucite in this area formed subsequently by contact metamorphism (metasomatism) of the magnesite during emplacement of a granodiorite intrusion in the Jurassic or Cretaceous.Stratigraphy of host rocks: upper member, Luning Formation, Upper TriassicLocality: Premier Chemicals Mine (also known as: Gabbs Magnesite-Brucite Mine / Basic Refractories Mine / Sierra Magnesite Mine), Gabbs Mining District, western flanks of the Paradise Range, Nye County, west-central Nevada, USA (vicinity of 38° 51' 53'' North latitude, 117° 53' 34'' West longitude)--------------------------------Photo gallery of magnesite:www.mindat.org/gallery.php?min=2482 |
| 撮影日 | 2025-03-19 18:49:38 |
| 撮影者 | James St. John |
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