A contribution to the study of FTIR spectra of opals

作者：Adamo Ilaria^*; Ghisoli Christian; Caucia Franca

来源：Neues Jahrbuch für Mineralogie - Abhandlungen, 2010, 187(1): 63-68.

DOI：10.1127/0077-7757/2010/0161

• opal
• X-ray powder diffraction
• mid-infrared spectroscopy
• micro-crystalline opal
• non-crystalline opal

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.

• 出版日期2010-3