五颜六色的黄龙玉及致色机理

黄龙玉是微晶质石英集合体。扫描电镜对黄龙玉石英晶间黏土矿物形成分析和能谱组分分析,表明石英晶间主要是胶状褐铁矿和泥质伊利石,黄龙玉石英微晶间充填物的种类、含量决定黄龙玉颜色。褐色胶状褐铁矿使玉石多呈红色调,黄色胶状褐铁矿物与伊利石混合物使黄龙玉呈浅橙色或黄色,黑色泥质伊利石黏土矿物使玉石带青、灰、黑等色调。黄龙玉中常见的"金砂"是玉石中含有自形黄铁矿而成,如果黄铁矿细小并沿层理分布,也会使黄龙玉呈现黑色。沿黄龙玉裂缝面树枝状分布的氧化锰构成了黄龙玉中的"水草"。充填物的含量一方面决定黄龙玉色的深浅,另一方面还影响着黄龙玉的透明度。充填物含量高,黄龙玉色深,透明度差;充填物含量低,黄龙玉色浅,透明度好;不含充填物就形成了透明的白色黄龙玉。

Coloring Mechanism of Huanglong Jade

Huanglong Jade is the aggregation of microcrystalline quartz mineral. Based on component and energy spectrum component analysis by scanning electron microscopy, the clay minerals that fill in space between the quartz crystals are limonites and illites. The colors of Huanglong Jade depend on the type and content of intercrystalline filling in microcrystalline quartz mineral. Red or brown colloidal limonite give it a red appearance, yellow colloidal limonite and illite make it appear light orange or yellow, and yellow or black illite give it a cyan, grey or black appearance. Golden sands, which occur commonly in Huanglong Jade, are the result of idiomorphic pyrites. If pyrites are tiny along with the bedding distribution, Huanglong Jade shows a black belt. Manganese oxide, along fracture surface dendrite distribution, constitute aquatic plants in Huanglong Jade. The tinges and transparency of the jade relate to filling materials. The higher content of the filling material, the darker and lower the transparency of the jade without filling materials, Huanglong jade appears colorless and transparent.