Rutilated quartz (Minas Gerais, Brazil) 3 : 無料・フリー素材/写真
Rutilated quartz (Minas Gerais, Brazil) 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 | Rutilated quartz from Brazil.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 5600 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.Rutile is a titanium oxide mineral (TiO2). It is an important titanium ore mineral. Rutile's most common crystal form consists of long, striated needles (acicular crystals). Rutile has an intense submetallic luster, a pale yellow to golden-brown to yellowish-brown to red to almost black color, and is fairly hard (H=6.5). Many twinned crystals have a bent or kinked appearance ("elbow twins"). Rutile occurs in igneous, sedimentary, and metamorphic rocks. It usually occurs as long, slender needles within quartz crystals (rutilated quartz) and in placer beach sands.Locality: unrecorded/undisclosed site in Minas Gerais State, southeastern Brazil------------------Photo gallery of rutile & rutilated quartz:www.mindat.org/gallery.php?min=3486andwww.mindat.org/gallery.php?min=3485 |
| 撮影日 | 2017-05-06 11:30:16 |
| 撮影者 | James St. John |
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