• Title/Summary/Keyword: pearl shells

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Optical properties and color analysis of various pearl shells (다양한 진주조개 패각의 색상 및 광학적 특성 분석)

  • Lee, Myung-Jin;Chae, Weon-Sik;Seo, Jin-Gyo;Park, Jong-Wan
    • The Korean Journal of Malacology
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    • v.25 no.3
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    • pp.203-210
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    • 2009
  • Optical properties and color analysis of nacreous layers were performed using various pearl shells. The cross section and microstructure of the surface in each nacreous layers were observed through a SEM (Scanning Electron Microscope), and the diffraction pattern on SEM images was analyzed using FFT (Fast Fourier Transform). Through these analysises, it was verified that the color and optical characteristics are closely related to the structure of nacreous layers. Incident angle-dependent reflection spectrum was used to examine the phenomena of color differenceas the direction of observation. Quantified values on the color change were obtained by CIE $L^*a^*b^*$ color scale. Using this research, database for the characteristics of natural pearl shells can be established, and the precise analytic method for observation of pearl shells was suggested.

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A Study on the Abalone Pearl Formation using Different Nucleus (핵종류별 참전복 진주 형성에 관한 연구)

  • KIM, Sung;PARK, Jong-Un;KIM, Jong-Hwa;PARK, Gwang-Chun
    • Journal of Fisheries and Marine Sciences Education
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    • v.15 no.2
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    • pp.219-225
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    • 2003
  • So far, for pearl culture using abalones, a plastic nucleus has been planted in an abalone by perforating the shell. But after planing 80 % of abalones died, and even if they live, the pearl's hardness was not so good. The weak hardness made the pearl valueless. The quality of a pearl is decided by the gloss and the quality of the pearl's layer. This study is to find the right nucleus for abalones and to decrease a death rate of abalones by selecting the right planting place. This study was also performed to obtain valuable pearls with proper size, gloss, and good color. Below is the result of the research; Conch shells out of the various nucleus materials were the best. Their shape, color and gloss were very good. The nucleus was planted in the part that a shell is grown up under the absorption ball, as a result a pearl sack was quickly made. After 15 days, out of every pearl, pearl sacks were made. The pearl formation was measured every month. From the abalone shell which was planted in April, qualitative pearls which was from 5mm to 5.81mm in size were obtained in December.

Textural, Isotopic, and Chemical Investigation of Cultured Pearls (양식진주의 조직적, 동위원소적 및 화학적 연구)

  • Woo, Kyung Sik
    • 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.

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The cultivation and characterization of imaged abalone pearls (문양화 전복진주의 양식 및 특성평가)

  • 박라영;김판채
    • 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.

A Study on the Material of Furniture in Goryeo (고려시대 가구재료 연구)

  • Cho, Sook-Kyung
    • Journal of the Korea Furniture Society
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    • v.25 no.1
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    • pp.19-27
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    • 2014
  • This paper studied the materials of the furniture which the noble men used in Goryeo, based on the furniture material category of solid wood furniture, lacquerware inlaid with mother-of-pearl and hardware. As for the solid wood furniture, the wood and furniture types are inferred based on the documents. The trees used for the wood furniture were zelkova, korean willow, pine, royal paulownia, maidenhair tree, korean pine, chinese juniper and elm. The furniture types were table, chair, wooden bench, small portable table, writing table, and folding screen. As to the types of lacquerware inlaid with mother-of-pearl, most of them were hams with top, which were made of abalone shells. The features of the lacquerware inlaid with mother-of-pearl were in detail and elaborate like the pattern of the full bloomed chrysanthemum. Writing tables were also made of lacquerware as pieces of furniture. Distinctively, the mother-of-pearl furniture material was popular enough to be used even in a horse saddle. Regarding the metal feldspar used as both a practical use and decoration, there are drop handle, hinge, the front basis, and lock seen in the artifacts, which were made of cast iron, bronze, and brass. Their manufacture techniques were eojamoon, bratticing and sheet metal. Through this study of the furniture materials used in Goryeo, it seems that Goryeo furniture focused on the functions rather than on the decorations, and in turn the forms were simple and basic. The technique of mother-of-pearl, a bit elaborate one, was used in the props furniture like kitchen wares, hams, or writing talbes. Probably, the solid wood is inferred to be used in a low wooden bench, a chair, and a table based on the documents.

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UV-Vis and ED-XRF Analyses of Natural Black Colored Pearls from Freshwater Cultured Shells (UV-Vis와 ED-XRF를 이용한 자연 색상의 담수 흑 양식진주 분석)

  • Kim, Hea-Yeon;Park, Jong-Wan
    • 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.

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An Experimental Study on Pearl Oyster (Pinctada fucata) Culture (인공진주 양식에 관한 시험연구)

  • CHO Chang-Hwan;KWON Woo-Seop;KIM Moo-Sang;KIM Nam-Gil;LIM Dong-Taik
    • Journal of Aquaculture
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    • v.1 no.1
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    • pp.85-102
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    • 1988
  • An experimental study on seedling production and wintering to develop pearl oyster, Pinctada fucata culture in Korea was carried out. from December 1986 to November 1988 in waters of Kori and of Seogwipo as wintering and of Eogu as culturing grounds. All pearl oysters as the sample were imported from Japan. The highest water temperature at Eogu was $23.6^{\circ}C$ in August and the lowest at Kori and Seogwipo were $13.2^{\circ}C$ and $14.0^{\circ}C$c in February, respectively, Phytoplankton was relatively plentiful but mortality of pearl oysters was $20.5\%$, which was twice at Seogwipo, due to high amount of suspended muds. It shows that Seogwipo is better wintering ground even though the amount of phytoplankton is lower than Kori. Average rates of pearl production after 6-months and 15-months period were $58.2\%$ and $48.3\%$ respecitively. Thickness of pearl layer and coating rate were also satisfactory. More than half of the pearls produced was so-called the pink-pearl, the best colour. About $10\%$ of them was the best quality. There were three peaks of D-shape larvae from July to September and it took about one month for D-shape larvae to become seed-shells. Settling was satisfactory and most of them settled at 1$\~$3 m layer and the best was 2 m-layer. Success of settling was supposed due to high water temperature and low precipitation than the normal year.

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Transformation Characteristics of Calcined Oyster Shell to Liquid Lime (소성된 굴패각의 액상소석회로의 전환 특성)

  • Ha, Su Hyeon;Kim, Yeongkyoo
    • Korean Journal of Mineralogy and Petrology
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    • v.33 no.3
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    • pp.185-193
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    • 2020
  • There have been many studies on the calcination of oyster shells in the perspective of recycling of resources. The quicklime made by the calcination of oyster shells is used either as it is or after reacting with water to transform to liquid lime before being used. However, the liquid lime made from calcined oyster shells show slightly different properties from that of limestone. In this study, to compare these properties of oyster shell with those of limestone, the samples were calcined and reacted with water at various temperatures to transform to a liquid lime and filtered using 150 ㎛ sieves to calculate the transform rate to liquid lime. The calcined limestone was transformed to liquid lime at all temperatures, but calcined oyster shell did not show any transformation at 30℃ and 50℃ under the experimental conditions of this study, and rather increased the weight for the remaining after filtration due to the presence of Ca(OH)2 produced by the reaction with water, Even at 90℃, the transformation rate of calcined oyster shell to liquid lime was lower than that of limestone. This difference in oyster shell can be explained partly by the preventing calcined one from reacting with water by conchiolin which is protein found in the prismatic and pearl layers of oyster shell. Conchiolin is also known to be stable and does not decompose even at high temperature. However, even the calcined chalk layer without conchiolin shows lower transformation rate than that of calcined limestone, probably due to the small amount of Na in oyster shell, which may cause additional reaction including eutectic melt during calcination process.