In 01.07.1999 he received the Allied Teaching Centre status to conduct teaching courses under the Gem-A (Gemmological Association of Great Britain) in Sri Lanka and commenced direct official contract to carry out teaching activities for Foundation and Diploma courses of Gem-A. Allied Gemmological Institute & Laboratory was established in 1999 under the sole proprietorship to conduct teaching courses in gemmology and also gemstone testing and issuance of laboratory testing reports to the public.
Mrs Gracelyn De Zoysa Jayatilleke, wife of Mr. Dayananda Dillimuni was a teacher in the government education service. After retirement from the service at C.W.W.Kannangara Vidyalaya in Colombo 08, she joined Allied Gemological Institute & Laboratory when it was opened up in 2010 at the new premises of 46.B.2, Galle Road, Colombo 03, to attend in gem testing activities. During this period she also qualified the Diploma in gemmology and finally graduated to obtain FGA qualifications of Gem-A. She continues to attending to gem testing activities of the AGIL.
Consultant and Chief Gemmologist of the Gemmological Institute of Colombo (GIC), Sri Lanka. Visiting Lecturer at Allied Gemmological Institute & Laboratory (AGIL), Colombo 03, Sri Lanka. In 2019 he received the appointment by the Gem-A as an ATC Tutor in Sri Lanka to conduct lectures at the Allied Gemmological Institute and Laboratory, Colombo, and he continues to teach gemmology as a visiting lecturer for the Foundation and Diploma courses at AGIL, in collaboration with Mr.Dayananda Dillimuni.