SPECIFYING QUARTZ CRYSTAL ORIKSTATION 



111 



vance in the positive s direction.) The y axis will always lie directly under 

 a major rhombohedral face. 



We could define the .v, y and s axes for a left-hand crystal as forming a 

 left-hand system. Though this is a useful conception in mathematical 



Fig. 2.3— A rhombohedron 



LEFT HAND 

 QUARTZ 



RIGHT HAND 

 QUARTZ 



Fig. 2.4 



studies, we can dodge this "double standard" by a simple device. For use 

 as a crystal circuit element, left-hand quartz can be used just as well as 

 right-hand quartz. In designing such an element it suffices to think al- 

 ways in terms of right-hand quartz and issue specifications for this kind 

 only, using always right-hand coordinate systems. If now for left-hand 



