Fluorite (Sweet Home Mine, Colorado, USA) : 無料・フリー素材/写真
Fluorite (Sweet Home Mine, Colorado, USA) / 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 | (public display, Denver Museum of Nature & Science, Denver, Colorado, USA)--------------------------------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 about 5500 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 halides are the "salt minerals", and have one or more of the following anions: Cl-, F-, I-, Br-.Fluorite is a calcium fluoride mineral (CaF2). The most diagnostic physical property of fluorite is its hardness (H≡4). Fluorite typically forms cubic crystals and, when broken, displays four cleavage planes (also quite diagnostic). When broken under controlled conditions, the broken pieces of fluorite form double pyramids. Fluorite is a good example of a mineral that can be any color. Common fluorite colors include clear, purple, blue, green, yellow, orange, and brown. The stereotypical color for fluorite is purple. Purple is the color fluorite "should be". A mineral collector doesn't have fluorite unless it's a purple fluorite (!). Fluorite occurs in association with some active volcanoes. HF emitted from volcanoes can react with Ca-bearing rocks to form fluorite crystals. Many hydrothermal veins contain fluorite. Much fluorite occurs in the vicinity of southern Illinois (Mississippi Valley-type deposits).The greenish material in the specimen seen here is the fluorite. It comes from the Sweet Home Mine, an old silver mine in Colorado.Locality: Sweet Home Mine, above Buckskin Gulch, south-southwest of Mt. Bross, northwest of Alma, Alma Mining District, eastern slopes of the northern Mosquito Range, far-western Park County, central Colorado, USA---------------------Info. on locality:www.mindat.org/loc-3690.html------------------------Photo gallery of fluorite:www.mindat.org/gallery.php?min=1576 |
| 撮影日 | 2013-10-26 14:43:07 |
| 撮影者 | James St. John |
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