South-Central Section–40th Annual Meeting (6–7 March 2006)

Paper No. 11
Presentation Time: 1:30 PM-5:10 PM

CHARACTERIZATION OF PRECIOUS SERPENTINE FROM BOOYEO, REP. OF KOREA


KIM, Won-Sa1, YEO, Jin-Young2, AHN, Hee-Jin2, KIM, Dong-Han2, CHOI, Lim3 and YOO, Seong-Mock2, (1)Geology, Chungnam National Univ, Daejeon, 305-764, South Korea, (2)Daejeon Sacience High School, Gusung-dong, Daejeon, 305-338, South Korea, (3)Daejeon Sacience High School, Gusung-dong, Daejeon, South Korea, kimw@cnu.ac.kr

A precious serpentine deposit was recently discovered in Booyeo County, Republic of Korea, and is the first recorded occurrence in the country. It forms along both contacts of a garnet vein intruding the serpentinite. The precious serpentine is semi-transparent and deep green with an oily luster. It is very tough and measured about 5 on Mohs' scale of hardness. Its Specific gravity and refreactive index are 2.57 and 1.56, respectively. X-ray powder diffraction data indicate that the precious serpentine is antigorite. The major chemical components are SiO2(42.49wt.%), MgO(39.08wt.%), Fe2O3(3.85wt.%), and H2O(11.87wt.%). Important trace elements include Cr(2188ppm), Ni(1110ppm), and Co(58ppm). An IR spectrum shows absorptions at 3670(OH stretching), 1190, 1070, 980(SiO stretching), and 610cm-1(OH bending). DTA/TGA thermogram gives peaks at 343, 755, and 830.1oC. The endothermic reaction at 755oC denotes expulsion of structural water, and the strong exthermic reaction at 830.1oC is related to the formation of olivine. Black inclusions finely dispersed in the mineral are identified, by X-ray gandolfi camera method, as magnetite.