and a distorted crystal in which parallel edges c and d replace the 

 points c and d, and the edge ab is elongated. 



Habit. Different continuations of the various forms in which a 

 substance may crystallize will produce crystals of widely varying 



c 



FIG. 45 a. Symmetrical Quartz Crystal. 



shapes, and especially when combined with distortions. These com- 

 1 )inations, peculiar to localities or conditions of crystallization, are 

 known as the habit. Forms will be found on crystals from one 



c 



FIG. 45 6. A Distorted Quartz. 



locality which may not necessarily be found on those from another. 

 Even though the forms are identical, their relative development will 



