CHARACTERIZATION OF PRECIOUS SERPENTINE FROM BOOYEO, REP. OF KOREA

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 830.1^oC. The endothermic reaction at 755^oC denotes expulsion of structural water, and the strong exthermic reaction at 830.1^oC is related to the formation of olivine. Black inclusions finely dispersed in the mineral are identified, by X-ray gandolfi camera method, as magnetite.