Some of the studied samples from Australia. Colors ranged from blue to dark blue, yellowish green, yellow, and greenish yellow to brownish yellow. Photo by Lhapsin Nillapat. Courtesy of Fura Gems.
Though long underappreciated, Australian sapphires could see a resurgence with the arrival of Fura Gems, a major mining and marketing company. A team of GIA researchers recently took a deeper look at the colors and causes of color of these sapphires, as well as the internal inclusion scenes observed.
The results are available in a study titled “Sapphires from Anakie, Australia: A Closer Look at Blue, Yellow, Green and Bicolor Sapphires.” The authors concluded that these sapphires are relatively high in Fe, resulting in their blue-green-yellow colors. Advanced statistical techniques can often help separate Australian sapphires from those in other deposits worldwide.
Source: gia.edu, Sudarat Saeseaw, Wim Vertriest, and Aaron Palke