The Identifying Characteristics Of Enhanced And Treated Agate

After inherited with a long time, the enhancement and treatment of agate have been modified for many times. People have got a great progress in the theory,technique, material of agate dying who could dye out tens of kinds of colors which could be classified into five systems, red, blue, yellow, green, black. This paper take the enhanced and treated agate as target, rely on normal gemology test, polarizing microscope, EMPA, X ray fluoresces, FIR spectra, Raman spectra and other tests to make research on the basic gemological characteristics, chemical components,structure feature and spectroscopy characteristics of the representative enhanced and treated agate and discusses identifying characteristics of their color and internal feature.The enhancement and treatment of agate could be classified into three methods,the direct heating, dying, and heating after dying. The normal gemology feature of enhanced and treated agate is basicly same with the natural agate. Rely on gemology microscope and scanning electron microscope, this paper find that there are many disorganized nail stripe on the whole surface or some parts of all the heated agate. The nail stripe formulated after the entrance of fuel and is related to the aggregation and crystallization of original inclusion in new position. It is the necessary results of the heat treatment and have identification meaning.The coloring block mess of the red heated agate is the ferruginous diffused halo of which the center is a cavity and is caused by different form of diffusion and decomposition of original ferruginous inclusion. The distributed direction of color band and color mass is vertical the growing direction of agate. The center of heated agate is light yellow to orange yellow and the near edge is red. The color is dense in the better growing position of crystal in the center of radical structure of agate.The color of dyed agate is dispersed distributed in the shape of fiber according to the self structure of agate. There are no other special coloring inclusion and the color is “float” on the surface. The same structure part of the color band have the same color concentration and there is no color transition change in the same band. The internal of agate may be colorless due to the different depth of dying.The X ray fluoresce spectra shows that the color element of dyed and heated agate includes Fe、Cr、Co, transition element Ga、Ge、Ir、Ta and Lanthanides element La 、Eu. Except the La(0.0073%), other element is all about 0.001% for the mass percent. These trace element could not bring harms to human body. The appearance of rare earth chemistry may instruct that new dye technique has been applied to the agate dying.The reflecting FIR spectra of enhanced and treated agate is the same to the natural agate of which the main components are quartz. The transmitted power FIR spectra have great differences with natural agate. The differences mainly reflect in the stronger absorb, vibration of organic matter, normal absorbed water and less structure water.The Raman spectra shows that the original ferruginous minerals of the heated red agate have completely changed into hematite. Other species of enhanced and treated agate have diffused color and no obvious identifying characteristics in the Raman spectra.