Raman spectroscopy of natural and cultured pearls and pearl producing mollusc shells

2019 ◽  
Vol 51 (9) ◽  
pp. 1813-1821 ◽  
Author(s):  
Stefanos Karampelas ◽  
Emmanuel Fritsch ◽  
Fatema Makhlooq ◽  
Fatima Mohamed ◽  
Abeer Al‐Alawi
Keyword(s):  
Raman Spectroscopy ◽  
Mollusc Shells ◽  
Cultured Pearls

scholarly journals IDENTIFICATION OF TREATED-COLOR FRESHWATER CULTURED PEARLS

2007 ◽  
Vol 40 (2) ◽  
pp. 794
Author(s):  
S. Karampelas ◽  
E. Fritsch ◽  
S. Sklavounos ◽  
T. Soldatos
Keyword(s):  
Raman Spectroscopy ◽  
Raman Scattering ◽  
Visual Observation ◽  
Raman Resonance ◽  
Natural Color ◽  
Wide Range ◽  
Green Excitation ◽  
Artificial Origin ◽  
Cultured Pearls

Demand for colored pearls has grown during the last thirty years. Colored pearls are rarer than white ones. Thus treated-color pearls have entered the marketplace and their identification became a challenge for the gemologists. With only the help of visual observation, EDXRF and X-radiography, methods that are used today for pearls identification, it is not always easy to identify them. Previous studies, have established that Raman scattering is useful to detect pigments in cultured freshwater pearls. The present study is based on the measurement of the Raman spectroscopy of 35 natural colored freshwater pearls and 15 treated-color freshwater pearls, covering a wide range of typical colors for this material, with green excitation. All natural- color pearls show the two major Raman resonance features of polacetyenic pigments assigned to C=C stretching-at about 1530(±25) cm'1- and C-C stretching - at about 1130(±10) cm' -, regardless of their specific hue. In this paper it is proposed that the absence of these Raman features prove the artificial origin of pigments in a colored freshwater cultured pearl.

Raman spectroscopy and X-ray diffraction of lithium niobate at temperatures up to 1300○-4.80pt○C

2005 ◽  
Vol 126 ◽  
pp. 101-105 ◽  
Author(s):  
B. Moulin ◽  
L. Hennet ◽  
D. Thiaudière ◽  
P. Melin ◽  
P. Simon
Keyword(s):  
Raman Spectroscopy ◽  
Lithium Niobate ◽  
X Ray Diffraction ◽  
X Ray

Raman spectroscopy using a gas laser

1965 ◽  
Vol 26 (11) ◽  
pp. 620-626 ◽  
Author(s):  
J.P. Russell
Keyword(s):  
Raman Spectroscopy ◽  
Gas Laser

OBSERVATION OF PRETRANSITIONAL EFFECTS ON THE SHAPE OF THE E2 (17 cm-1 ) OPTICAL MODE IN β-Ag1 BY RAMAN SPECTROSCOPY

1981 ◽  
Vol 42 (C6) ◽  
pp. C6-776-C6-778
Author(s):  
E. Cazzanelli ◽  
A. Fontana ◽  
G. Mariotto ◽  
F. Rocca ◽  
M. P. Fontana
Keyword(s):  
Raman Spectroscopy ◽  
Optical Mode

RAMAN SPECTROSCOPY IN GUIDED OPTICAL WAVES

1983 ◽  
Vol 44 (C10) ◽  
pp. C10-501-C10-503 ◽  
Author(s):  
J. D. Swalen ◽  
J. F. Rabolt
Keyword(s):  
Raman Spectroscopy ◽  
Optical Waves

A POWERFUL TOOL TO STUDY COLLISIONAL PHENOMENA AND FOR COMBUSTION APPLICATIONS : THE HIGH RESOLUTION STIMULATED RAMAN SPECTROSCOPY

1987 ◽  
Vol 48 (C7) ◽  
pp. C7-761-C7-762
Author(s):  
B. LAVOREL ◽  
G. MILLOT ◽  
R. SAINT-LOUP ◽  
M. L. GONZE ◽  
J. SANTOS ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Resolution ◽  
Stimulated Raman
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