No, not all sapphires from Sri Lanka are heat treated. In fact, most of the natural sapphires from Sri Lanka reach the market without being heat-treated or colour treated thanks to the precision cutting techniques used by our expert gemstone cutters. However, Sri Lankan gem dealers do use heat treatment on sapphires to add value to the gemstone through colour enhancement. Mostly on occasions when the raw sapphires may contain irregular colour patches, due to rutile inclusions in the stone.