Tay Thye Sun has been practicing gemology after he graduated from the * Gemological Institute of America since 1980. Before he went full time on gem testing lab work and instructor, he was an experienced gem dealer and doing wholesale and retail jewellery business. In 1985, he came across some of the natural rubies with very little inclusions and very difficult to authenticate the nature of the rubies. This prompted him to find out more and in doing so had slowly drawn him into the world of gem research.
To date, he and together with his many co-authors published many articles in the gemological journals around the world.
One of his notable work is determining a 2,600-kg green statue to see whether it is jade. He collaborated with the National University of Singapore and Singapore Polytechnic and found out that the piece was green feldspar, not jade.
He was invited to speak in APEC Melbourne 2000, APEC Beijing 2000, 60th Anniversary of the German Gemmological Association 1992 (click to view pictures), Germany; and the prestigious meeting by invitation only of the International Gemmological Conference held in Spain 2001, India 1999, Germany 1997, Thailand 1995, etc.