Colombo, Dec 13 (IANS): The world's largest natural corundum blue sapphire, named the "Queen of Asia", weighing around 310 kg was unveiled on Sunday.

The rare gem stone had been found three months ago from a gem pit in Ratnapura, popularly known as gem city situated around 85 km away from capital Colombo, but it was only shown for the first time at the residence of the gem pit owner on Sunday.

The National Gem and Jewellery Authority, the state-run institute, certified the immensely valuable gem stone and plans are underway to sell it at an international market.

 Thilak Weerasinghe, Chairman of the National Gem and Jewellery Authority, said that more tests are to be carried out on the gem stone.

"There could be more clean stones inside this and there are already one or two clean stones which are could be seen from outside."

International gem organisations are yet to certify the precious stone.

Gem expert Chamila Suranga said that the specialty of this gem is that the gem stone is comprised of aluminum oxide, titanium, iron, and nickel.

"With the present economic situation in the country it has been decided to present this gem to the world and plans are underway to sell it at the highest amount in the international market."

In July, the world's largest star sapphire cluster too was found from Ratnapura. Weighing around 510 kg carats, the cluster named the "Serendipity Sapphire" was found accidentally while digging a water well.