A proficient expert invited to test a South African “diamond” that claims to be the world’s largest is full of doubts about its claim. Ernest Blom, president of the World Federation of Diamond Bourses has now withdrawn fully from the verification process of the stone. Blom’s requirement of witnessing the stone has not been met. Weighing 8,000-carat, this diamond dugged by the South Africa’s north-west province was considered to be more than twice the size of the world’s largest diamond of 3,000-carat discovered in 1905.