The Standard For Yellow Sapphires
Yellow sapphires can range in color from greenish yellow to orangish yellow and everything in between. The preferred yellow sapphire color is a medium, vibrant canary yellow.
What Gives These Exceptional Gems Their Color?
The popularity of yellow sapphires has grown in the past few years due to their close resemblance to yellow diamonds, which have also been sought after due to publicity by their famous celebrity owners. There are two very different causes of yellow coloration in sapphires. The most common cause is the trace element iron. In general, increased iron concentrations will increase color saturation. The trace element titanium causes an undesirable green cast in yellow sapphires, and the most valuable stones are relatively titanium-free. Yellow sapphires can also be colored naturally by low-level radiation within the earth or by lab-induced irradiation. Lab-induced sapphires are not harmful to humans or radioactive but their color has been known to fade with exposure to heat and light. For this reason, most consumers avoid them. We test all our yellow sapphires for signs of irradiation treatment by various methods, such as exposing the gemstones to UV light.
Besides irradiation, yellow sapphires are frequently subjected to intense heat and diffusion treatments. Heat treatment transforms worthless rough into marketable gems, vastly increasing the supply of attractive yellow sapphires on the market today. Unheated yellow sapphires with strong saturation remain quite rare.
How Does Cut Affect The Color?
Yellow sapphires frequently have fewer inclusions than other colors, and they are held to higher clarity standards than blue, pink, or padparadscha sapphires. Yellow sapphire’s relative clarity is quite convenient, since the medium tone at which the color shows best does little to hide inclusions. Yellow sapphire rough has traditionally been less costly than blue, pink, or padparadscha, so cutters don’t compromise brilliance in favor of weight retention. As a result, well-cut yellow sapphires are easier to find than other sapphire colors and are more readily available in specialty cuts.
Where Can They Be Found?
Yellow sapphires are found in Tanzania, Madagascar, Thailand and Australia, although Sri Lanka is the primary source. Perhaps the most rare but sought after sapphire color for those in the know are the brilliant and beautiful orange pink gems known as padparadscha.