The colour of illite jade is of distinct gradation which is related to the content of hematite in different sedimentary bed.
The colour of illite jade is of distinct gradation which is related to the content of hematite in different sedimentary bed.
该玉石的颜色层次结构清楚，分界明显，与不同沉积层中赤铁矿的质量分数有关。