The rough diamond weighs 20.09ct and was purchased in West Africa. The shape is octahedral with rounded points and ribs. A large feather inclusion is situated on one of the faces that extend from the surface to approximately one third into the diamond. The rough diamond will be oriented so that a large clean piece can be obtained and the smaller piece positioned to minimize the large feather inclusion.
The rough diamond is shown mounted in a sawing pot with the smaller included piece exposed. Notice the black ink line that will direct the sawyer during the sawing operation. This type of off-centered sawing is called topping.
The diamond is mounted in a sawing machine and lowered into a revolving blade that spins at approximately 8,500 RPM. The edge of the blade is coated with diamond powder and periodically changed during the sawing process. It took approximately 21 hours to saw through the entire 20.09ct rough.
We can clearly observe that the rough was separated into two pieces. The smaller piece weighs 7.56ct and the larger piece 12.23ct. This gives us a weight loss of 0.30ct. Which represents 1.5% loss during the sawing process. (By comparison, standard weight loss during sawing averages 2%)
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