Chrome diopside is a vibrant green variety of diopside that is colored by chromium, and to a lesser extent iron. Clean, bright stones above 2 carats are rare. The only known commercial deposit of gem quality chrome diopside is in the Republic of Sakha in Siberia, Russia. Yakutsk, the capital city, has the coldest winter temperatures for any major city on earth. Mining can only take place during the summer months due to the extreme winter conditions in Siberia.