Mostly, around 95% of the


Mostly, around 95% of the times, Yellow Sapphires/Blue Sapphires/Ruby from Bangkok are heat treated/diffusion treated/glass filled/color enhanced. However, sapphires from Ceylon (Sri Lanka) are generally untreated but they can also be treated when required. So, it is best to buy gemstone that are certified from GIA/IGI/GTL etc. to be sure that the gemstone that you’re buying is treated or not.