Apophyllite (Momin Akhada, Maharashtra State, India) 3 : 無料・フリー素材/写真
Apophyllite (Momin Akhada, Maharashtra State, India) 3 / 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 | Apophyllite from India.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 5400 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 silicates are the most abundant and chemically complex group of minerals. All silicates have silica as the basis for their chemistry. "Silica" refers to SiO2 chemistry. The fundamental molecular unit of silica is one small silicon atom surrounded by four large oxygen atoms in the shape of a triangular pyramid - this is the silica tetrahedron - SiO4. Each oxygen atom is shared by two silicon atoms, so only half of the four oxygens "belong" to each silicon. The resulting formula for silica is thus SiO2, not SiO4. The simplest & most abundant silicate mineral in the Earth's crust is quartz (SiO2). All other silicates have silica + impurities. Many silicates have a significant percentage of aluminum (the aluminosilicates).Apophyllite is a small group of hydrous phyllosilicate minerals. Their nomenclature has changed several times over recent decades. The general chemical formula for apophyllite is (K,Na)Ca4Si8O20(F,OH)·8H2O - hydrous potassium sodium calcium fluoro-hydroxysilicate. End-member varieties include fluorapophyllite, hydroxyapophyllite, and natroapophyllite.Apophyllite has a nonmetallic, glassy to pearly luster and ranges in color from clear and white to many other colors, depending on impurities. It has a white streak and is moderately hard (H = 4.5 to 5). Apophyllite crystallizes in the tetragonal system and has one perfect cleavage.Locality: unrecorded/undisclosed site at or near Momin Akhada, west of the town of Rahuri, Maharashtra State, India---------------------Photo galleries of apophyllite:www.mindat.org/gallery.php?min=283andwww.mindat.org/gallery.php?min=1573andwww.mindat.org/gallery.php?min=1989andwww.mindat.org/gallery.php?min=2851 |
| 撮影日 | 2018-05-05 11:58:14 |
| 撮影者 | James St. John |
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