leaving the walls with their embedded crystallites intact. (The appearance of this altered enamel in the electron microscope is similar to that of the section shown in Fig. 1. Photographs are of a ...

they appear as 'pointed' inclusions at the edge of large crystallites. In Fig. 1 a few examples of such 'pointed' crystals are indicated by C. From an analysis by Sandee 1 (cf. also refs.