成分点 meaning in English

composition point

Speaking from its outline , shallow and deep color existing alternately is the direct reason why the bands emerged , while the periodical change of the total fe content in the sapphire is the foundmental reason ; in the same band of the same sapphire , the total fe content is nearly the same , so in this sense any spot can respresent the whole band in which the spot lies ; in one sapphire , the deep - color band must contain the higher fe than the shallow one ; the sapphire which exists bands must have a black or a dark blue core , where the fe content is usually higher than other bands . 2
研究表明，山东昌乐的蓝宝石普遍发育环带，从外观上讲，蓝宝石中深浅色度的交替出现是出现环带的直接原因，而总fe含量的近周期性变化是形成蓝宝石环带的根本原因；同一蓝宝石的同一环带，其总fe的含量几乎相同，所以该环带上的任何一个成分点都可以代表整条环带的成分；同一蓝宝石的不同环带，颜色越深，含fe越高，颜色越浅，含fe则越低；凡出现环带的蓝宝石，其核部总是深黑色或者蓝黑色，而其含铁量一般都比其它部位高。