By a method similar to that used in petrofabric analyses, a correlation between crystallographic boule orientation and processing results is shown for synthetic corundum made in America by the well-known Verneuil process. For best processing results, the growth axis of a synthetic corundum boule should lie approximately normal to a second order pyramid face with indices {1122}. A second favorable orientation is close to {8190}. Boules grown normal to various faces in the zone of negative rhombohedrons generally show irregular to hackly fracture when split, and yield definitely inferior results in jewel-bearing manufacture. Economic savings could be effected if boule manufacturers would control the orientation of their product.

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