A FTIR spectra collection of a large number of various micro-crystalline (C and CT) and non-crystalline (A) opal samples is here presented. The suite of the investigated specimens consists of the most important natural and synthetic opal samples, with a gemological significance, present on the market today, including both with and without play of color. The opal-C type is clearly identifiable on the basis of the sharp peak at about 620 cm-1, whereas the FTIR spectra of opal-CT and -A differ mainly for the position of the 790 cm-1 SiO band. Other phases, such as i.e. clay minerals, present in opal samples and related to different genesis and localities, can be easily detected by mid-infrared spectroscopy, in addition to X-ray powder diffraction data.
A contribution to the study of FTIR spectra of opals / I. Adamo, C. Ghisoli, F. Caucia. - In: NEUES JAHRBUCH FUR MINERALOGIE-ABHANDLUNGEN. - ISSN 0077-7757. - 187:1(2010 Mar), pp. 63-68.
Titolo: | A contribution to the study of FTIR spectra of opals |
Autori: | ADAMO, ILARIA (Primo) |
Parole Chiave: | Micro-crystalline opal; Mid-infrared spectroscopy; Non-crystalline opal; Opal; X-ray powder diffraction |
Settore Scientifico Disciplinare: | Settore GEO/06 - Mineralogia |
Data di pubblicazione: | mar-2010 |
Rivista: | |
Tipologia: | Article (author) |
Digital Object Identifier (DOI): | http://dx.doi.org/10.1127/0077-7757/2010/0161 |
Appare nelle tipologie: | 01 - Articolo su periodico |