The diamond cutter who had the honor of splitting the world’s largest diamond, about 5 inches long, was Jacob Ascher. On the afternoon of February 10, 1908, he cut a groove with another diamond (since only diamonds can cut diamonds) in just the right place, as carefully as he could calculate, then he laid a blade in the groove and tapped on it. The diamond broke, and Jacob immediately fainted. When he recovered, he discovered that the diamond had broken just right, exactly as he had hoped.