Size of a Girdle Chip (16.24)
The cautious approach when buying damaged goods is to get the millimeter gauge working for you by measuring from the depth of the chip to its opposite undamaged girdle area. Subtract an additional 2/10ths of a millimeter or more for the girdle and you should be very
close to the finished diameter of the stone. Figure the depth percentage to be close to what the original was and you will have the numbers necessary for the weight estimation formula.