Yellow Sapphire stands nine over the hardness scale holding the 3rd placement soon after Diamond and Moissanite. If your gemstone is more than one carat then it can't have clean edges. Colour: Since the purest Variation from the family of sapphires, these white gems are usually of the highest quality https://www.apsense.com/article/810029-some-historical-facts-about-sri-lankan-yellow-sapp.html