THE WORLD’S LARGEST PRODUCER OF IDEAL CUT DIAMONDS WITH PERFECT HEARTS AND ARROWS, SPECIALIZING IN SIZES 0.60MM to 4.29MM Four generations of passionate precision are what make our ideal cut diamonds pure perfection. Grunberger Precision Cut® diamonds are available in more than 40 different qualities. They can be calibrated within 0.00250 of a millimeter, ensuring that they will match and fit the settings you designed while being the most beautiful choice you can make. No matter the size or clarity, we cut the perfect diamond.