Sri Lanka: World's largest star sapphire cluster found in backyard

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Sri Lankan authorities say the world's largest star sapphire cluster has been found in a backyard - by accident.

A gem trader said the stone was found by workmen digging a well in his home in the gem-rich Ratnapura area.

Experts say the stone, which is pale blue in colour, has an estimated value of up to $100 million in the international market.

The cluster weighs around 510 kilograms or 2.5 million carats and has been named the "Serendipity Sapphire".