THE TECHNIQUE OF HEAT TREATING 'GEUDA' AND PRODUCING BLUE SAPPHIRES Guthila Wijesuriya July 24, 2021 See More
Modern Application of Gemstone Inclusions: Detection of Colour-Enhancement Potential od GEUDA SAPPHIRE from Sri Lanka Guthila Wijesuriya July 24, 2021 See More
A portable Super Heating Chamber, Invented for heat treatment of natural or pre heated ... Guthila Wijesuriya July 24, 2021 See More
