Mineraloške karakteristike i poreklo boje opala iz lokaliteta Bare, Šumadija

Mineralogy and color origin of opals from the locality Bare, Šumadija

Abstract

Three representative samples of opals, intensively colored (green, yellow and red) from the locality Bare were investigated. The study of opals was carried out by means of the chemical, x—ray powder diffraction, thermal analysis as well as by infrared and optical absorption spectra. All data allowed identification of opals as opal-CT and proved that color is directly connected with the presence and concentration of iron.