Sri Lanka displays the rarest blue sapphire weighing 683 pounds

Sri Lankan authorities on Sunday put on show what they said was the world's largest natural corundum blue sapphire, weighing 683 pounds (310 kilograms), which was found in a gem pit about three months ago.
The stone was found in the gem-rich Ratnapura area where local people had also previously found the world's largest star sapphire cluster in a backyard by accident. Ratnapura is known as the gem capital of the South Asian country, which is a leading exporter of sapphires and other precious gems.
Local gemologists, who have examined the sapphire, said it was one of the rarest gems in the world. International organizations are yet to certify the precious stone.