.游鈞量-小小的島 (Mini Island)

茫茫的斜長石海中，出現一片猶如小小的島的黑雲母。初時乍看土氣十足，換個角度看，竟然黯淡無光。但只要用心點，加上一片偏振片，就能看見動人光輝的生命力！屬於鐵鎂質礦物的黑雲母，解理方向、輪廓相當清晰；轉動時，因為雙折射進入黑雲母的兩道光速度不同，所以會產生多色性的現象，黃色部分轉動後會變成黑色。當加上偏振片之後轉動後會平行解理方向消光；另外，亮綠色的干涉色，其顏色則和燈光有關。

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In Plagioclase crystal, a mini island-like biotite is found among the sea of tectosilicate minerals. At first sight, it appears rustic; switching to another angle, it looks/seems gloomy. However the island is brought back to life after adding a polarization filter. The biotite, a common mineral within the mica group, has a perfect bascal cleavage; the multicolor effect is created from double refractions of light entering the mineral. By turning the open nicol, the yellow part becomes black. When added with a polarization filter, turning the cross nicol will make light disperse horizontally on the cleavage angle; the interfering green tint is also caused by lighting effect.

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