中文名:堇青石

英文名:Cordierite

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後設資料

資料識別:
系統識別碼:0b00000180033576
資料類型:
型式:合集
紀錄類別:礦物知識單元
主題與關鍵字:
學域-大分類:地質-岩礦類
礦物分類:矽酸鹽
描述:
簡介:"堇青石的英文名稱為Cordierite,乃是為了紀念法國地質學家P. L. A. Coedier而命名,而寶石級的堇青石,英文名為Iolite或Dichroite。Iolite係源於希臘語,為「紫羅蘭」的意思,象徵寶石級堇青石的顏色特徵。堇青石具有明顯的多色性,用肉眼從不同角度觀察,可以發現它的顏色有明顯的變化。化學組成為富含鐵、鎂、鋁的矽酸鹽,成分中的鎂可被鐵或錳所置換,而部分的鋁也可被鐵所取代。晶體多呈短柱狀,在晶體內偶而含有矽線石、尖晶石、鋯石、磷灰石、雲母等包裹體。顏色一般呈淺藍、深藍或灰藍色,部分為無色、白、灰、淺黃、淺紫或淺褐色,而經過風化的,則略帶綠色。如果風化程度增加,堇青石可變為雲母、綠泥石或是滑石。   堇青石是由含鋁量較高的岩石,經過中度到高度熱力變質作用所形成,主要產在片麻岩或含鋁量較高的片岩中。質量較佳的寶石級堇青石多產在斯里蘭卡和印度,此外,德國、緬甸、坦尚尼亞、芬蘭、馬達加斯加、美國等國也有產出。CordieriteIntroductionCordierite is named after P.L.A Cordier, the French geologist who first discovered it. The gemstone variety of this mineral is called Iolite or Dichroite. The name Iolite has its stem from Greek, meaning “violet”, which represent the characteristic colors of gemstone grade cordierite. Exhibiting prominent pleochroism, cordierite may change its color depending on the angles of observation. Its chemical composition is silicate rich with iron, magnesium and aluminum. Magnesium in these minerals may be replaced by iron or manganese, and portions of aluminum may also be replaced by iron. The crystals of cordierite are columnar and short, and inclusions such as sillimanite, spinel, zircon, apatite, and mica are occasionally found in them. The colors may appear pale blue, deep blue or grayish blue; some maybe transparent, white, gray, pale yellow, purple or brown. Weathered cordierites may carry shades of green, and if the weathering continues, cordierite may become mica, chlorite or talc. Cordierite typically occurs in rocks with high aluminum contents and transformed by middle to high thermal contact metamorphism. They can be found in gneiss or schists with high aluminum contents. Good quality gem grade cordierites are produced in Sri Lanka and India ; some of them are also found in Germany , Myanmar , Tanzania , Finland , Madagascar , and the United States . "
晶系:斜方
集合體型態:塊狀
解理(斷口):解理
顏色:黃
光澤:油脂
比重:2~2.99
出版者:
數位化執行單位:國立自然科學博物館:地質學組岩礦學
格式:
材質:岩石
硬度:7~7.9
範圍:
國內產地:綠島和蘭嶼的安山岩中
國外產地:美國Connecticut的Haddam、New London、Guilford和Plymouth
管理權:
典藏單位:國立自然科學博物館
使用聲明:館內公開瀏覽

授權聯絡窗口

數位典藏相關業務聯絡人:謝玉鈴小姐
04-23226940*786
ling@nmns.edu.tw

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