Optical and Cathodoluminescence Investigations of the Green Microcrystalline (Chrysoprase) Quartz

Abstract

Gem-quality green cryptocrystalline silica formation is relatively rare in nature, and has an interesting mineralogical crystallization and irradiation response of the fine fibrous silica. Chemical analyses of the green material reveal remarkable concentrations of some trace elements, such as nickel, iron, and chrome. They are certainly responsible for producing of the individual color production and irradiation luminescence response. Optical absorption spectroscopy shows that the dark green coloration is due to light transmittance at 528 nm in the visible region as a result of absorbance peak at 645 nm and about 360-410 nm absorbance band gap. These optical absorbance gaps are due to not only Ni ion content (4600 ppm) but also, Fe ion (13600 ppm) and Cr ion (823 ppm) contents. The cathodoluminescence spectra of the green material were taken into consideration in this study, and they were evaluated using “surpher, grapher, and axum” of the computer programs. In the spectra of alternative current cathodoluminescence with two-dimension, one major spectral emission band appears at readable intensity and magnitude in 90 Hz in the yellow wavelength region at 585 nm. In addition, the two-dimension cathodoluminescence spectra show that only the other major spectral emission band of cathodoluminescence appears at 90 Hz frequency in the green wavelength region at 530 nm.