A 158.20-carat rare yellow diamond has been discovered at the Diavik Diamond Mine in Canada’s Northwest Territories. The find, made in March 2025 and announced by Rio Tinto on April 1, 2026, originated from one of the world’s most remote mining sites, located on a small island in Lac de Gras about 200 kilometers south of the Arctic Circle. The mine operates off the national power grid and is accessible only by ice road in winter or floatplane in summer.

According to Rio Tinto, the diamond formed around two billion years ago deep within the Earth. Its yellow hue results from nitrogen atoms in its structure, making it exceptionally rare and valuable. Yellow diamonds account for less than one percent of Diavik’s total production, and this is only the fifth yellow diamond from the mine weighing over 100 carats.

The Diavik mine officially ceased operations in March 2026, making this discovery one of its final major finds. The diamond’s market value has not yet been disclosed, and cutting and sale processes have not begun.