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The mineral bastnäsite (or bastnaesite) is one of a family of three carbonate-fluoride minerals, which includes bastnäsite-(Ce) with a formula of (Ce, La)CO3F, bastnäsite-(La) with a formula of (La, Ce)CO3F, and bastnäsite-(Y) with a formula of (Y, Ce)CO3F. Some of the bastnäsites contain OH- instead of F- and they receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium and other rare earth elements. Bastnäsite was first described by the Swedish chemist Wilhelm Hisinger in 1838. It is named for the Bastnäs mine near Riddarhyttan, Västmanland, Sweden.〔 Bastnäsite also occurs as very high quality specimens at the Zagi Mountains, Pakistan. Bastnäsite occurs in alkali granite and syenite and in associated pegmatites. It also occurs in carbonatites and in associated fenites and other metasomatites.〔〔(Bastnasite ). Mineral Galleries. Retrieved on 2011-10-14.〕 ==Composition== Bastnäsite has cerium, lanthanum and yttrium in its generalized formula but officially the mineral is divided into three minerals based on the predominant rare earth element.〔Beatty, Richard; 2007; Th℮ Lanthanides; Publish℮d by Marshall Cavendish.〕 There is bastnäsite-(Ce) with a more accurate formula of (Ce, La)CO3F. There is also bastnäsite-(La) with a formula of (La, Ce)CO3F. And finally there is bastnäsite-(Y) with a formula of (Y, Ce)CO3F. There is little difference in the three in terms of physical properties and most bastnäsite is bastnäsite-(Ce). Cerium in most natural bastnäsites usually dominates the others. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium, an important industrial metal. Bastnäsite is closely related to the mineral series parisite.〔Gupta, C. K. (2004) Extractive metallurgy of rare earths, CRC Press ISBN 0-415-33340-7〕 The two are both rare earth fluorocarbonates, but parisite's formula of Ca(Ce, La, Nd)2(CO3)3F2 contains calcium (and a small amount of neodymium) and a different ratio of constituent ions. Parisite could be viewed as a formula unit of calcite (CaCO3) added to two formula units of bastnäsite. In fact, the two have been shown to alter back and forth with the addition or loss of CaCO3 in natural environments. Bastnäsite forms a series with the minerals hydroxylbastnäsite-(Ce) () and hydroxylbastnäsite-(Nd). The three are members of a substitution series that involves the possible substitution of fluoride (F−) ions with hydroxyl (OH−) ions. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bastnäsite」の詳細全文を読む スポンサード リンク
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