Optical Properties and Natural Radioactivity Levels of Turkish Natural Glass Obsidian

Abstract

Obsidianis a naturally occurring volcanic glass formed as an igneous rock. It is a kindof alumino-silicate glass containing iron impurities and some tiny particles(particle-dispersed glasses). It can be found in black, gray, brown, blue, andgreen colors in nature. In recent work, the obsidian specimens in black andbrown colors were collected from Sarıkamış which is a small town in Karsprovince located at the north-east part of Turkey. The obtained specimens werethen cut and polished to obtain two parallel surfaces to perform opticalmeasurements. The optical absorption spectra of the samples were collectedunder ambient environment. The natural radioactivity levels of the specimenswere also measured using a gamma spectrometer whıch uses a NaI(Tl)scintillation detector for the determination of the radioactivity.