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Titration
Raman shift(cm-1
)
Figure 3 – Raman spectra of diamond, moissanite, and quartz measured on inVia confocal Raman microscope from Renishaw (West Dundee, IL). (© Copyright Renishaw plc. All rights reserved. Image reproduced with permission of Renishaw.)
Electrochemistry
Ion Chromatography
Spectroscopy
Laboratory
Process
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Figure 4 – Spectral differences between natural red coral and dyed coral. The spectral peaks for red coral are 1129 cm-1 1089 cm-1
and 1517 cm-1 ; for dyed coral there is a single, high-intensity spectrum at
(© Copyright Gem Testing Laboratory, Jaipur. All rights reserved. Image reproduced with permission of Gem Testing Laboratory, Jaipur.)
gemstone based on the Raman spectral ID com- parison to the library spectra for gemstones from various sources. A Raman spectrom- eter produces precise and distinctive spectra for all classes of minerals containing borates, carbonates, halides, native elements, oxides, phosphates, silicates, sulfates, and sulfides.
As shown in Figure 1, diamond has a carbon– carbon vibration Raman spectrum showing a single Raman shift at 1332 cm-1
, which confirms
the authenticity of pure diamond. Silicon wafer has a signature Raman shift at 520 cm-1 Raman shift at 300 cm-1 is a germanium.
. The indicates the gemstone AMERICAN LABORATORY 33 JUNE/JULY 2017
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