Duftite-calcite 4 : 無料・フリー素材/写真
Duftite-calcite 4 / 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 | Duftite-calcite (public display, Minnesota Discovery Center, Chisholm, Minnesota, 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 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 arsenate minerals all have one or more arsenate anions (AsO4 -3).Duftite is a scarce lead copper hydroxy-arsenate mineral, PbCu(AsO4)(OH). It has a nonmetallic luster, a greenish color, a whitish to pale greenish streak, and a moderate hardness (H = 4.5). It lacks cleavage, has conchoidal fracture, and forms small crystals or botryoidal masses. Duftite occurs in the oxidized alteration zone above some polymetallic mineral deposits.The beautiful specimen shown above consists of numerous small greenish-colored duftite crystals on larger blocky crystals of calcite.Locality: unrecorded/undisclosed-----------------Photo gallery of duftite:www.mindat.org/gallery.php?min=1325 |
撮影日 | 2015-06-11 10:51:07 |
撮影者 | James St. John |
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