National Geographic : 1950 Dec
B. Newman-Three Lions Aiming at Perfection, the Cutter Risks Disaster Pen and ink trace lines of cleavage on the surface of a rough diamond. After weeks of study, the stone is grooved to receive a mallet tap at the likeliest spot (page 780). A slight mistake may cause the gem to fly into a hundred bits. An unsuspected flaw will do the same. National Geographic Photographer Willard R.Culver Upon a MalletTap Hangs aDiamond's Future Cleavage of this 100-caratSouth African stone yielded three finegems. Lazare Kaplan, a New Yorkdiamond cutter, struck thecritical blow while his son Leo held the blade. Thetwo gained recognition several years agofor cleaving the 726-carat JonkerDiamond, part ofwhich isshown onpage 781.