Jonker diamond , world ' s largest , to be split by expert 's single blow . A single blow , delivered by Lezare Kaplan the diamond cutter , after days of study , will split the famous Jonker Diamond , largest in the world , into three pieces .The 726 carats stone split into three pieces will then be divided into eleven smaller stones and will be made into a necklace valued at nearly half a million pounds . Kaplan has been studying the stone for many days to find the exact angle at which his blow will be struck . Photo shows , a representative of the 瞿 400 , 000 necklace that isto be made from the Jonker Diamond . 7 May 1936 *** Local Caption ***