Elementary research on color-forming mechanism of turquoise

On account of the complexities of mineralogical composition,structure and bond,the factors of leading to the variation of color are complicate.The color of a mineral is often the effect of many factors.Turquoise is a kind of jade that shows its own color,that is to say,the color of turquoise is determined by its own components and structures.Through microprobe analysis,the turquoise's components of distinct color are studied,and the result shows that turquoise's color is decided by Cu²⁺ ions and Fe³⁺ ions,the basic color of turquo ise is related tothe existence of Cu²⁺ octahed ron,whhis beneficia leffect,but Fe³⁺ ions lead to the reverse.The cry stal field and the spectrum experiment analysis getthe coincident conclu sion.The differential thermal analysis(DTA) and thermal analysis get the conclusion that some effects on the color of turquoise a recome in to being because of absorped water and cry stalline water:the more the absorped water contains,the deeper the color is.When it is heated to 300℃(turquoise loses a part of or the whole crysta lline),turquoise's color is changed obviou sly from blue to green.