• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.6
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• pp.315-319
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• 2003

The quality, quantity, color, and characteristics were found out cultured seawater pearls and freshwater pearls. In the XRF measurement Ca chemical combinations were the main elements and Sr was detected at higher levels for the sea-water pearl and Si, S, Ca, Mn, P and other elements were found at higher levels for the fresh-water pearls. Such differences is judged to be caused by the ion diluted in sea and fresh water which affects the pearl elements. Although near similar structural peak was shown for the FT-IR measurement, the fresh-water pearl showed a lower peak for the 2344 wave. For the results of PL, the peak for fresh-water measured with Hd-Cd Laser at 455 nm was higher and with the Ar-ion Laser measurements, peaks were high at 545 nm and 570 nm for fresh-water pearl and sea-water pearls respectively.

• Journal of the Mineralogical Society of Korea
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• v.28 no.1
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• pp.9-16
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• 2015

A mineralogical analysis on the factors affecting the luster of pearls was carried out using gravity measurement, optical microscope observation, X-ray diffraction analysis, and scanning electron microscopy. We divided the seawater cultured pearls from Tongyeong into the following four types based on luster and shape; good luster and round (LR), lackluster and round (LLR), lackluster and baroque (LLB), and lackluster and two nucleus (LTN) pearls. Pearls with high-quality luster had slightly lower specific gravity as compared to pearls with low-quality luster, but both these types of pearls are within the specific gravity range of commercial pearls. Regarding the cross-sectional thickness of the mother-of-pearl layer, LR pearls showed a uniform thickness of about 0.3 mm in average. On the other hand, LLR pearls were characterized by relatively thinner, but uniform thickness. LTN and LLB pearls showed a tendency of significantly large variation in thickness even within a single pearl. For the surface of pearls, pearls with high-quality luster showed narrower and clearer growth lines of aragonite crystals as compared to pearls with low-quality luster. Pearls with high-quality luster were characterized by fewer aragonite crystal lattice defects as compared to pearls with low-quality luster, and the former showed parallel arrangement, thinner thickness, and less difference in thickness on the surface and inside. If a pearl has a prismatic layer, it is composed of aragonite with calcite in the prismatic and nacreous layer, and calcite content is very high in the lackluster pearl. Pearls without a prismatic layer were devoid of calcite irrespective of their quality of luster, and were composed of aragonite.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.245-254
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• 2012

This project analyzes distinct qualities of pearl cultured in Tongyeong by physical, chemical and optical test. The result is to provide scientific data for the value of pearl from Korean seawater. It divides one year pearl, which is used as a sample in the project, into white, natural blue and yellow gold colors, and then it has been divided into A, B and C based on the quality of the last results. A chemical experiment demonstrates that the higher quality has lower protein content of less than 10%. In another test called heavy metal content test, there is no big difference among classes. In the characterization of spectroscopy, it shows 280 nm peak indicated the conchiolin. It is clear that 407 nm, 430 nm and 460 nm peak are White group that are not in processed condition.

• The Korean Journal of Malacology
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• v.27 no.3
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• pp.247-252
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• 2011

The effect of ${\gamma}$-ray irradiation on the color of nucleus and cultured pearls was investigated. After ($^{60}Co$) ${\gamma}$-ray irradiation on the pearl nucleus, its color was altered from brownish to blackish brown or gray depending on irradiation dose. It was clearly found that the all samples are composed of aragonite. ESR spectra were based on the measurement of the paramagnetic species $CO_2$-radicals by the interaction with the ${\gamma}$-ray irradiation in $Mn^{2+}$ containing $CaCO_3$. In this study, we investigated optimal detection method of ${\gamma}$-ray irradiation to establish destructive or non-destructive test for pearl nucleus.