• 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 Journal of the Korea Contents Association
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• v.10 no.11
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• pp.154-161
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• 2010

With Jewelry industry is becoming active with gradual increase of transactions of pearl and diamond. The pearl market of recent times the size of that market was magnified because the pearls of various type are imported. The necessity of new design development and grasps properties of pearl is demanded clearly because like that. This research analyzed the cultivated brown pearl and black pearl which is sold from market with gemological Analysis. As result, it is ascertained the dyed fresh water pearl. I suggest the design which uses the chocolate brown color pearl beads which the consumers prefer and another pearl design which is concept of wedding gift through CAD/CAM works.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.4
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• pp.152-156
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• 2005

The cultivation of akoya pearls was carried out with bio bead nucleus prepared using the hydroxyapatite. The akoya pearls cultured with bio bead nucleus were shown the color of cream. The luster and orient effect created by an action of the light from nacre were magnificent. The result of XRD is found that the nacre is a calcium carbonate of aragonite form. From the result of SEM, it is found that layers of calcium carbonate and conchiolin are stratified. The properties of akoya pearls cultured with bio bead nucleus are same those of akoya pearl cultivated with bead nucleus made from washboard shell. Because of the bio bead nucleus developed in this study has such a high capacity in producing various sizes and shapes, it is very advantageous for the cultivation of akoya pearls.

• 한국해양학회지
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• v.24 no.2
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• pp.69-78
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• 1989

Cultivated pearls, composed of aragonite crystals, show two distinctive layers: nacreous and conchiolin organic layers. Each aragonite crystal is surrounded by organic matrix, which probably consists of amino acids. Nucleus, surrounded by pearl layer, also consists of nacreous crystals, suggesting that there is a close mineralogical and ultrasturctural relationship between pearl and nucleus. Carbon isotopic values of cultivated pearls are within the range of marine carbonate carbon. Oxygen isotopic composition indicates that the temperature for the growth of pearl and pearl oyster ranges from 16.4 to $21.4^{\circ}C$ and from 15.5 to $24.8^{\circ}C$, corresponding to the summer temperature range of the cultivating area. Elemental composition of pearl, pearl oyster, and nucleus shows that there is a difference in chemical composition depending upon the original mineralogy and the chemical composition of water in which shells grow. Especially, a strong relationship exists between pearl and the inner layer of pearl oyster because both are composed of nacreous aragonite and formed in a shallow marine environment.

• 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 Korean Crystal Growth and Crystal Technology
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• v.14 no.2
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• pp.78-81
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• 2004

The nacre of imaged abalone pearls was obtained as a calcium carbonate of aragonite type. This result was same the nacre of natural abalone pearl. From the observation of SEM for the nacre adhered on the pearl nucleus, it was known that the layers of calcium carbonate and conchiolin were stratified. The growth rate of nacre was found to be 0.0056∼0.0074 mm/day, which is twice faster than that of traditional method used shells. The pendant and brooch were manufactured using the imaged abalone pearls.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.5
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• pp.205-210
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• 2008

Pearl is the organic gemstone which does not come from mines but from the biomineralization inside mollusc. Mollusc with nacre on inner surface of the shell is inevitable to make pearl. In this paper we researched and analyzed the pearls cultured using Pen shell (Atrina pectinata) which is not used in pearl farming industry but has potential to make pearls because it has thick and beautiful nacre inside the shell. SEM analysis was conducted to reveal the pattern of nacre on the Atrina pectinata pearl. Specific characteristics as sea-water pearl are detected by further analysis with ED-XRF. Aragonite specific peaks such as $1083cm^{-1}$ and $705cm^{-1}$ were shown by Raman analysis. UV-Vis analysis of Atrina pectinata pearl showed different pattern of spectrum compared with Pinctada margaritifera pearl. The reason for this discrepancy is assumed by the metabolic difference of each species.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.4
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• pp.215-223
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• 2010

A seasonal circulation patterns in the Chinju Bay (CB) were suggested from the observed data at two channels of the Noryang Channel (NC) and the Daebang Channel (DC) during the period from 2005 to 2008. The water circulation in the CB is mainly controlled through the NC and the DC. In winter, tidal current at the surface layer of the NC flows from the Kwangyang Bay (KB) eastward into the CB, whereas the current at the bottom layer flows from the CB westward into the KB. In summer, tidal current at the surface layer of the NC goes from the CB westward into the KB. The flow system at the NC shows the typical pattern of thermohaline circulation. In spring, tidal current at the surface layer of the eastern part of the DC flows out into southeastern open ocean. However, in summer, the current in the western part of the DC flows into the CB through the DC. Also, the velocity in the western part of DC is 50~70 cm/sec stronger than that in the eastern part. To obtain better understanding on the seasonal circulation pattern in the NC and the DC, additionally the detailed studies on the field measurements and three dimensional numerical modeling are needed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.201-211
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• 2022

At the center of the Noryang waterway, the Gwangyang bay area (including the Yeosu Strait) is located at the west, and the Jinju bay area (including Gangjin bay and Sacheon bay) is located at the east. Freshwater from several rivers is flowing into the study area. In particula,r the event of flood, great quantities freshwater flow from Seomjingang (Seomjin river) into the Gwangyang bay area and from Gahwacheon (discharge from Namgang Dam) into the Jinju bay. The Gwangyang and Jinju bay are connected to the Noryang waterway. In addition, freshwater from Seomjingang and Gahwacheon also affect through the Noryang waterway. In this study, we elucidated the characteristics of the tidal exchange rate and residence time for dry season and flood season on 50 frequency, considering freshwater from 51 rivers, including Seomjingang and Gahwacheon, using a particle tracking method. We conducted additional experiments to determine the effect of freshwater from Seomjingang and Gahwacheon during flooding. In both the dry season and flood season, the result showed that the particles released from the Gwangyang bay moved to the Jinju bay through the Noryang waterway. However, comparatively small amount of particles moved from the Jinju bay to the Gwangyang bay. Each experimental case, the sea exchange rate was 44.40~67.21% in the Gwangyang bay and 50.37~73.10% in the Jinju bay, and the average residence time was 7.07~15.36days in the Gwangyang bay and 6.45~12.75days in the Jinju bay. Consequently the sea exchange rate increased and the residence time decreased during flooding. A calculation of cross-section water flux over 30 days for 7 internal and 5 external areas, indicated that the main essential flow direction of the water flux was the river outflow water from Seomjingang flow through the Yeosu strait to the outer sea and from Gahwacheon flow through Sacheon bay, Jinju bay and the Daebang waterway to the outer sea.

• The Korean Journal of Malacology
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• v.24 no.3
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• pp.243-251
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• 2008

Analyses of UV-Vis spectrum and reflectance are useful tools to identify pearls of which color was naturally made or chemically changed. Contents of some trace elements of pearls by using ED-XRF may give us the information that the pearls were originated from marine shells or freshwater shells, and may give us whether the pearls were chemically treated or not. Three types of chemically untreated pearls, freshwater cultured, Akoya cultured and Tahitian cultured, were treated with silver nitrate. UV-Vis absorbance spectrum of Ag was changed after treatment, and reflectance of pearls was decreased. Absorbance of natural black colored Tahitian cultured pearls at 400, 500 and 700 nm was observed. Natural black colored freshwater cultured pearls showed two characteristic absorption patterns in UV-Vis spectra at 380-400, 480-500 nm. Unlike naturally black colored Tahitian cultured pearls, the absorption spectrum at 700 nm could not be found from black freshwater cultured pearls. Manganese was not detected in the pearls from marine shells, and strontium content of the pearls from marine cultured shells was higher than that from freshwater cultured shells. According to ED-XRF analysis, Ag contents of silver nitrate treated pearls increased as more time passed, because silver ion invaded to nacre layer of the pearls. Since Ag content of the black pearls known as untreated ranged under 0.1%, analysis of Ag content may used to distinguish the black pearls are treated or not in marketplace.