Bright Orange Sapphire from Greenland

The Aappaluttoq mine in Greenland is home to the oldest known ruby-bearing rocks on Earth. These host rocks are nearly three billion years old (A. Polat et al., “New age (ca. 2970 Ma), mantle source composition and geodynamic constraints on the Archean Fiskenæsset anorthosite complex, SW Greenland,” Chemical Geology, Vol. 277, No. 1-2, 2010, pp. 1–20). This deposit was initially known for producing translucent to opaque ruby and pink sapphire, much of it cut into cabochon form. However, transparent material has always been found in this mine and makes up about 5–10% of the production.

At the AGTA show, Greenland Ruby displayed many examples of attractive transparent ruby and pink to orangy pink sapphire, including several fancy-color sapphires in sizes greater than one carat (figure 1; see also a color study of fancy sapphire from Greenland in this issue). These fancy colors are achieved by heat treating nearly colorless to slightly pink transparent material. A transparent bright orange sapphire weighing 0.89 ct and measuring 6.41 × 5.02 mm (figure 2) immediately caught our eye. Martin Viala, product manager for Greenland Ruby, shared with us a video of the original 1.07 g sapphire rough (see below). This unusual stone was mined in late 2019 and heated in May 2022. Viala noted that it was a textbook example of a chromium trapped-hole (h●–Cr3+) chromophore (E.V. Dubinsky et al., “A quantitative description of the causes of color in corundum,” Spring 2020 G&G, pp. 2–28).