Can Yellow Sapphires be Heat Treated?

Simple Answer, Yes. Can you heat every yellow sapphire ? NO.

There is a certain type of yellow sapphires that can be heat treated to enhance the color. Gems miners and local dealers are well experienced to spot these yellow sapphires. In Sri Lanka we call them ''kowangu pushparage'' ''KO-ONE-GU'' .

Below picture is traditional age old technique of heat treating sapphires.

Traditional way of heating sapphires.

Also, in my view heated yellow sapphires can take a slight orange tone and is low in value compared to a natural unheated Ceylon Yellow sapphire.

How do you identify a Kowangu Yellow Sapphire?

One can only determine if a Yellow Sapphire is a KO-ONE-GU by closer inspection with a gem torch . KO-ONE-gu is a type of very fine silky strips that is inside a yellow sapphire. These once heat treated will enhance the color of a yellow sapphire.

Hope you learned something from this.

If you ever need to purchase a yellow sapphire from Sri Lanka you can contact me via duleeka@naturalyellowsapphires.com