Dielectric behaviors at microwave frequencies and Mössbauer effects of chalcedony, agate, and zultanite**Project supported by the Project LO1305 and Operational Program Education for Competitiveness-European Social Fund of the Ministry of Education, Youth and Sports of the Czech Republic (Grant No. CZ.1.07/2.3.00/20.0155), and the Internal Student Grant IGA of Palacky University in Olomouc, Czech Republic (Grant No. IGA PrF 2014017).

Abstract

In this study, dielectric properties within 8–12 GHz microwave frequencies, inductively coupled plasma-atomic emission spectrometry, Fourier transform infrared spectrometry, synchronized two thermal analyses, and 57Fe Mössbauer spectroscopy analysis of chalcedony, agate, and zultanite samples from Turkey are presented. Agate and chalcedony show the same nine vibrational absorption peaks obtained unlike zultanite from FTIR spectra in the 350 cm−1 to 4000 cm−1 range, ε′ values of chalcedony, agate and zultanite derived at 10.5 GHz were 4.67, 4.41, and 7.34, respectively, ε′ and ε″ values of the studied samples at the microwave frequencies are related to the percentage weight of their constituent parts in their chemical compositions. 57Fe Mössbauer spectroscopy results confirm the existence of iron-containing islands in the crystal structure of zultanite, agate, and chalcedony samples, equipped them with magnetic features typical for magnetic nanoparticles including superparamagnetism. The presence of iron-containing islands significantly affects the magnetic, dielectric, and optical properties of studied samples that are not observed for pure minerals without any foreign inclusions.