A 5.43-carat oval from the Singida region of Tanzania in a deep cinnamon-orange with the strong dispersion and high refractive index characteristic of zircon as a species. Zircon is one of the earth's oldest minerals — individual crystals from certain deposits have been dated to over four billion years — and the orange material from Singida sits among the most optically active of any warm-toned gemstone. Unheated. The color is original to the crystal.
 
5.43 carats / 12.1 × 8.1 × 5.7 mm / Unheated