"Fracturing" categories:

A:  Minor cracks;  few or no cracks are conspicuous 
     to the naked eye and no cracks penetrate the entire
B:  Moderate cracks;  several cracks extend across 
     exterior surfaces and the specimen can be
     readily broken along the cracks.
C:  Severe cracks;  specimen readily crumbles 
     along cracks that are both extensive and