• 作者： 譚立平；王執明；陳其瑞；田沛霖；崔伯銓；俞振甫
• 作者服務機構： 國立臺灣大學地質學系; 國立成功大學地球科學系; 美國東加羅林納大學地質學系; 國立臺灣大學物理學系
• 中文摘要： 臺灣軟玉可分?普通玉、?眼玉、及羊脂玉三種，化學成分接近純透閃石，僅含十分之一之陽起石。軟玉中以?眼玉內之透閃石纖維排列最規則，平板方向大致?(100)方向，維氏硬度可達1166，相當莫氏硬度7，垂直纖維方向?(001)方向，硬度較低。軟玉之翠綠色與?有關。建議以綠?指數、透明度、及包裹物多寡，將軟玉分類。 在蛇紋岩與黑色片岩接觸帶中有軟玉、透輝石、透長石、黝簾石、斜黝簾石、鈣鋁榴石、鈣?榴石、水鈣榴石、符山石 、方解石、及石英。在蛇紋岩中有橄欖石、葉蛇紋石、密綠泥石、鉻鐵礦、磁鐵礦、磁?鐵礦、?銅礦、?鐵礦、滑石、水鎂石、菱鎂礦、白雲石、及霰石。
• 英文摘要： Nephrite is a very important economic mineral in Taiwan. The value of the nephrite sold retail in Taiwan amounts approximately to 10 billion N. T. dollars annually. The people directly and indirectly involved I in the nephrite business in Taiwan total 200,000. Some nephrite carvings recently made by the lapidaries in Taiwan are as excellent as those displayed in the National Palace Museum, and are almost entirely sold to foreign countries. The Taiwan nephrite may be classified as common, cat's-eye, and waxy or mutton-fat nephrites. Common nephrite is the traditional nephrite, characterized by a vitreous luster and a platy habit. Cat's-eye nephrite is characterized by a silky luster and a chatoyency which is caused by fibrous structure. Waxy nephrite is characterized by a waxy appearance, caused by cryptocrystal-line texture. Bowenite has been sold as nephrite but it is a serpentine. The Taiwan nephrites are tremolitic, with Mg/(Mg + Fe+Mn) atomic ratios from 85.5 to 92.2, density from 2.96 to 3.04, α0 from 9.75 to 9.94, b0 from 17.94 to 18.11, c0 from 5.11 to 5.32, α from 1.602 to 1.610, β from 1.622 to 1.628, γ from 1.625 to 1.635. The hardness ranges from 472 to 1166 in Vickers hardness, equivalent to 5. to 7 of Mohs scale, the latter value being higher than the hardness for nephrite and tremolite reported in geologic literature. The tremolite fibers in nephrite are arranged in some crystallographic orientations, with the c axis of the fibers perpendicular to the fibrous structure. The a (100) face, which is parallel to the schistosity of the country rocks, is harder than b (010) and c (001). Cat's-eye phenomenon can be observed on (100) and (010), but not on (001). Absorption is stronger on (001) than on other faces, so that a cabochon of common nephrite polished on (001) shows a green color deeper than those polished on (100) and (010), and consequently it can be sold at a higher price than those polished on (100) and (010). Chromite, picotite, gros-sularite, serpentine, and chalcopyrite are the common inclusions in the nephrite. Spectrographic analyses of 53 Taiwan nephrites give, in average, 36 ppm Co, 1044 ppm Cr, 17 ppm Cu, 1346 ppm Mn, 647 ppm Ni, 10 ppm V, and 24 ppm Ti. Eight serpentinite samples, which are associated with nephrite, contain similar amounts of these trace elements. White and green nephrites contain approximately the same amount of FeO. Cr and Ni are responsible for the brilliant-green color of tremolitic nephrite.
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