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Celsian is an uncommon feldspar mineral, barium aluminosilicate, BaAl2Si2O8. The mineral occurs in contact metamorphic rocks with significant barium content. Its crystal system is monoclinic, and it is white, yellow, or transparent in appearance. In pure form, it is transparent. Synthetic barium aluminosilicate is used as a ceramic in dental fillings and other applications. The mineral is named after Anders Celsius (1701–1744). == Composition == Celsian is a barium feldspar with a chemical composition BaAl2Si2O8. It forms part of the feldspar group and belongs to the celsian-hyalophane series and the celsian-orthoclase series. It has some resemblance to anorthite, and it has four distinct polymorphs. The essential elements are Si,Al,O and Ba. Some common impurities in the mineral are Fe, Ti, Mg, K and Ca. Celsian is stable from room temperature up to 1590 °C ( Lin and Foster,1968). The most common trace elements are potassium and calcium, in an analysis of the approximate chemical composition of celsian the following wt% were found: • 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「Celsian」の詳細全文を読む スポンサード リンク
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