R1: Characterization and description of minerals (Joint Session with The Gemmological Society of Japan)

[R1-07] Microtexture of talc associated with copper minerals

*Zhenghao Zhao¹, Kentaro Emori¹, Makoto Okano¹, Xuejing He², Hiroyuki Kagi², Hideto Yoshida² (1. Central Gem Laboratory, 2. Univ. of Tokyo Sci.)

Keywords:Talc, IR Spectra, Raman Spectra, XRD, SEM

We analyzed some light-blue minerals that look like chrysocolla associated with azurite and malachite. However, the results of EDS analysis show that these light-blue minerals contain high concentrations of Mg that should not be present in chrysocolla. The combined results of infrared absorption spectra, Raman spectra, and XRD show that these minerals are actually talc. SEM-EDS and EPMA results show that the samples are composed of talc and unidentified copper silicate.