Alrosa mined the largest gem-quality diamond in the last 10 years at the Mayat diamond mine in the Anabar district of Yakutia. Weight of the diamond is 390.7 carats. Diamond found is a light crystal of non-standard shape, bordered by a yellow-brown halo - a unique combination of mass, shape and color to date. Previously, the largest gem-quality diamond weighing 401 carats was found ten years ago, in 2013.