• Korean Journal of Soil Science and Fertilizer
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• v.6 no.1
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• pp.33-34
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• 1973

Jeondanto which is known a edible earth material in the legend of local people on the Mt. Baegdeog at Yeongweul Gun, Gangweon-Do, is one of pure and well crystalized kaolinite having a thin hexagonal platy structure by X-ray, DTA and electron microscope analysis. Even though its extent is currently unknown, Jeondanto will be one of interesting materials for mineralogical study of its uniquely well crystalized structure.

• Journal of the Mineralogical Society of Korea
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• v.9 no.1
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• pp.26-34
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• 1996

The white leather-like playgorskite occurs as a vein in the Cretaceous sedimentary rocks in the Yeongsan area, Kyeongnam, Korea. It has been investigate by means of XRD, TEM, DTA-TG, IR and chemical analysis. The palygorskite vein is composed mostly of well-crystallized palygorskite. The wall rock of the vein is altered to smectite along both sides of the vein. According to TEM observation the palygorskite shows a fibrous habit. The sizes offibers are quite variable, ranging from 0.1 to 3.0 micron in length. From XRD data, the palygorskite has orthorhombic unit cell with a=12.726$\AA$, b=17.796$\AA$, c=5.1666$\AA$. The chemical formula of the palygorskite was calculated as [Si7.93Al0.07](Al1.91Fe+30.11Mg1.96)Ca0.01O20(OH)4(OH2)2.

• Journal of the Mineralogical Society of Korea
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• v.8 no.2
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• pp.86-90
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• 1995

본 연구에서는 전자현미분석기를 이용한 스틸프로멜레인의 분석시 발생하는 K 이동현상을 체계적으로 조사하였다. 분석시료가 전자빔에 오래 노출될 경우 K이 주변으로부터 이동하여 K 함량이 높게 측정되는 경향이 있다. 가속전압과 빔전류를 낮추고 전자빔 크기를 크게 할 경우 일반적으로 K의 이동은 줄어드는 경향을 보여준다. 실험결과에 의하면 5-$\mu\textrm{m}$ 이상 크기의 전자빔을 사용하고 15kV의 가속전압 및 3nA의 빔전류 조건에서 분석할 경우 비교적 정확한 K 함량을 측정할 수 있음을 알 수 있다. 전자현미분석기를 사용하여 스틸프노멜레인의 K 함량을 측정하는 경우 K이 모이지 않도록 주의해야 하며, 스틸플로멜레인의 분석결과를 보고하는 경우에는 분석시 사용된 전자현미분석기의 조건도 함께 나타내는 것이 바람직하다.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2005.05a
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• pp.50-57
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• 2005

Although the bulk composition of materials is one of the major considerations in extractive metallurgy and environmental science, surface composition and topography (edges and dislocations are preferred sites for physicochemical reactions) control surface reactivity, and consequently play a major role in determining metallurgical phenomena and pollution by heavy metals and organics. An understanding of interaction mechanisms of different chemical species with the mineral surface in an aqueous media is very important in natural environment and metallurgical processing. X-ray photoelectron spectroscopy (XPS) has been used as an ex-situ analytical technique, but the material to be analyzed can be any size from $100{\mu}m$ up to about 1 cm. It can also measure mixed solids powders, but it is impossible to ascertain the original source of resulting x-ray signals where they were emitted from, since it radiates and scans the macro sample surface area.

• Journal of the Mineralogical Society of Korea
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• v.2 no.1
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• pp.8-10
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• 1989

Sphene from the McDonald pegmatite near Bancroft, Ontario, Canada was analyzed using EPMA. It contains 4.3 to 6.3 weight percent of Nb2O5 with an average formula Ca1.02(Ti0.62Al0.22Nb0.07Fe0.06Ta0.01)Si0.99(O4.85F0.16). Three types of subtitutions are possible; 1)2Ti4+=(Nb, Ta)5+ + (Al, Fe3+), 2) Ti + O = (Al, Fe3+) + (F, OH), and 3) 2Ti + O = Fe2+ + (Nb, Ta)5+ + (F, OH). T재 different schemes of substitutions for balancing the analysis are considered when the iron is either all ferric or all ferrous. Assuming stoichiometry fo Ca and Si, a general formula derived from the two different schemes is Ca(Ti0.64Al0.22Fe3+0.06-X {{{{Fe_{x}^{2+} }} Nb0.01)Sio4.80-XF0.16(OH)0.04+x.

• Journal of the Korean Geotechnical Society
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• v.16 no.6
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• pp.51-58
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• 2000

울산지역에 널리 분포하고 있는 해성 퇴적토에 대하여 깊이별로 물리, 화학 그리고 광물학적 특성을 파악하였으며, 이 지역에서 채취된 시료에 대하여 깊이별로 퓨준압말시험을 실시하였다. 본 논문을 위하여 울산 해성 퇴적토의 생성과정을 추정하고, X-선 회절 분석, X-선 형광분석 및 에너지분산분광분석을 실시하여 깊이에 따른 변화를 비교하였다. 울산 해성 퇴적토의 점토광물에 대한 정량분석결과, 일라이트, 카올리나이트, 녹니석, 스멕타이트 순으로 많게 나타났음, 화학성분 분석결과, SiO$_2$, $Al_2$O$_3$그리고 Fe$_2$O$_3$가 대부분을 차지하는 것으로 나타났다. 주사전자현미경 관찰결과, 유공충과 규조류가 관찰되었다. 표준압밀시험 결과, 울산지역의 해성 퇴적 점토는 깊이에 따른 변형거동이 화학적, 광물학적 분석결과와 마찬가지로 깊이에 따른 변화를 보이지 않아 같은 시디에 퇴적인 것으로 판단된다.

• Journal of the Mineralogical Society of Korea
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• v.3 no.2
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• pp.65-71
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• 1990

Compositions and thermal changes of pyrrhotites from Ohtani and Uljin mines were examined by Arnold's method and DTA analysis. The results are as follow: 1) The compositions of hexagonal type pyrrhotite are in some range from 47.23-47.42 atom.% Fe in the Ohtani mine, and 47.40-47.64 atom.% Fe in the Uljin mine. 2) The compositions of hexagonal pyrrhotite with exsoluted lamellae of monoclinic pyrrhotite are in 47.35-47.50 atom.% Fe in the Ohtani mine, and 47.15-47.40 atom.% Fe in the Uljin mine. This fact does not agree with phase diagrams of Fe-S system shown by Nakazawa and Morimoto(1970) and Sugaki and Shima(1977). 3) DTA data show two endothermic peak corresponding to ${\gamma}$ and $\beta$ transformation. Sturctural conversions from order(intermediate) to disorder(high) forms occur at about $300^{\circ}C$ for hexagonal type and further lower temperature with increasing Fe-content.

• Journal of the Mineralogical Society of Korea
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• v.32 no.4
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• pp.259-271
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• 2019

We evaluated mineralogical, physical property and accelerated weather resistance of cinnabar, realgar and orpiment used as cultural heritages and traditional paintings. JB and JS are sample names of cinnabar and JH and UH are sample names of orpiment and Realgar, respectively. As a result of mineralogical property evaluation, Jinsa was identified cinnabar (HgS) and there was no difference in chemical composition according to the grade. UH and JH were confirmed realgar (AsS) and orpiment (As₂S₃), respectively. The polarization characteristics such as shape and color indicate that pigments using our test were natural mineral pigment observed by polarization microscope. Especially, in the case of cinnabar, it is not easy to distinguish between natural mineral pigment and synthetic pigment. But the results of polarization microscope said that cinnabar is natural occurring mineral which have authentic mineral particle and unevenly fracture. As a result of thermal analysis, JH has a higher glass transition temperature and heat stability than UH. After accelerated weather test, cinnabar, realgar and orpiment were striking result in color change because of light degradation. Red color of cinnabar turn into black and the color of realgar and orpiment became brighter than before. JB (meta-cinnabar) is more photosensitivity and faster becoming dark than JB (cinnabar). Finally light transforms realgar (red, As₄S₄) in arsenolite (As₂O₃).

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.23-32
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• 2018

Noerok ia a green pigment used in Joseon dynasty, and its main usage was for forming foundation layers of Dancheong, the ornamental paintings on the surface of traditional buildings in Korea, such as the Daeung-jeon(main hall) of Bulguk-sa temple. In this research, we investigated the mineralogical characteristic changes of Noerok, a traditional Korean pigment, depending on its firing temperature. The Noerok that we experimented on was mined from Noeseong Mountain, Pohang where it is locally reserved. The major composition mineral is Celadonite, and the main constituent elements are Fe, Si, K and Mg, that refers to the existence of Fe-rich mica. As a result of phased firing experiment from $105^{\circ}C$ to $1000^{\circ}C$, the color was changed from green to pale green, then to brown, and finally to red in order. In the thermal analysis, endothermic reaction induced by the dehydration of crystalline water was confirmed at around $616^{\circ}C$. In the mineralogical change, the crystal surface [($11{\bar{1}}$) and ($02{\bar{1}}$)] of the mineral collapsed at temperatures above $600^{\circ}C$, and iron oxide was formed at $1000^{\circ}C$ or higher. Therefore, it is estimated that the crystallization temperature of Noerok is below $600^{\circ}C$, and it is also considered that it has undergone the alteration phase up to stage I, based on the presence of only a celadonite.

• Journal of the Mineralogical Society of Korea
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• v.30 no.1
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• pp.11-19
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• 2017

Reddish brown clay-silt sediments covered granitoid weathering crust in the Jangdongri area, Naju, Korea. Mineralogical and geochemical properties of the ~2 m sediment section were investigated. The sediments were composed mainly of quartz (50%) and clay minerals (45%) with minor contents of K-feldspar, goethite, hematite, and gibbsite. The clay minerals were illite, illite-smectite mixed-layers, vermiculite, hydroxy-Al vermiculite, kaolinite, and halloysite. Mineral composition varied little through the section with the minor upward enrichment of plagioclase and chlorite. Abundant illitic clay minerals indicated the remote source of the sediments because clays derived by granite weathering in Korea were dominated by kaolin minerals. A comparison with the mineral composition of Asian dust (Hwangsa) suggested that plagioclase and K-feldspar disappeared by chemical weathering after deposition, resulting in the quartz and clay-rich sediments. Plagioclase and chlorite altered to kaolin and vermiculite, respectively. Goethite and hematite derived by the weathering of iron-bearing minerals stained the sediment to reddish brown color. The mineralogical and geochemical properties of the reddish brown clay-silt sediments were consistent with those of eolian deposits identified in Korea, supporting eolian origin of the Jangdongri sediments, requiring future confirmation including age dating and isotopic analysis.