Various regions of several diamond specimens were explored with nuclear radiations of differing penetration. All the specimens showed some increase in the electric charge trap density towards the natural surface, but large differences occurred in the absolute magnitudes. Consideration of the present results and of others obtained by using different optical and electrical techniques leads to the conclusion that diamonds which show good electrical conduction pulse properties are composed of layers of highly perfect crystalline material separated by relatively few, and much thinner, partial barriers of imperfect material. If the average thickness of the crystallite layers is about 10$\mu $, then the specimen has the texture necessary for a good counter. The poorer counting shown by some specimens composed of still larger crystallites is attributed to the presence of wider barrier layers.