Yellow sapphires are some of the most beautiful and sought-after gemstones that come in very clean large sizes. The increasing popularity of yellow diamonds and yellow engagement rings have in-turn increased the demand for yellow sapphires as well. They come in a range of colours between greenish-yellow to bright canary yellow. Although the most popular yellow sapphire is a medium canary yellow, some Asian markets have a high demand for a deep orangish-yellow (whisky colour).
One of the main reasons for the yellow colour in a sapphire is the presence of iron traces. Hence, the more the iron concentration, the higher the colour saturation. Low-level radiation within the earth or lab-induced irradiation can also create yellow sapphires. However, such gemstones can fade with exposure to light and heat. Yet, heat treatments have expanded the market of yellow sapphires and increased demand. Natural yellow sapphires that are not heated and contain saturation are scarce and rare. They are relatively clean and very bright with excellent light reflection in every lighting condition.
Compared to other sapphire colours, yellow sapphires have fewer inclusions and have higher clarity range. Sometimes minor traces of titanium can form an unwanted green speck in yellow sapphires. The lesser the quantity of titanium, the more valuable the gemstone becomes. While sapphires of other colours have higher traces of titanium-bearing rutile silk, it is less common in yellow sapphires. The clarity and transparency of yellow sapphire are other factors determining the value of the stone.
Yellow sapphires are less expensive than their counterparts in blue, pink, or Padparadscha (a mixture of orange and pink). Therefore, gem cutters tend to give prominence to the brilliance of the stone as opposed to weight retention. Consequently, well-cut yellow sapphires are more common than other sapphire colours. Moreover, yellow sapphires are also available in speciality-cuts like radiant cuts that bring out the exquisite colour of the gem.
Sri Lanka is the primary source of yellow sapphires in the world. However, it is also available in Madagascar, Tanzania, Australia and Thailand.