EXPLANATION OF PLATE 38. 



BENITOITE. 



Planes shown: c(0001), rt(ll20), m(10T0), ^(OITO), p(lOTl), tt(OITI), 

 c7(22Il). 



1. Habit characterized by great development of the negative prism ^ 

 and found on a number of crystals. 



2. Habit characterized by great development of the positive prism m. 

 It is in general not uncommon for in to be broader parallel to the vertical 

 axis than ,u. 



3. Habit characterized by second order forms d and a found with but 

 slight variation in 10 crystals in a lot of 500 examined. The oscillatory 

 striations between c and p are often found instead of r(10T2) and appeared 

 in front upper sectant of crystal from which the drawing was made. 



4. Detail of part of a crystal showing a coarse development of the 

 oscillatory growth zone between c and p. Of two crystals on which this 

 coarse development was found, one had the second order hexagonal prism 

 a (as figured) without d, and the other d without a. 



ALBITE. 



5. 5a. Albite in simple albite twin from druse. P(001), M(010), 

 1(110), T(1T0), r>(120), /'(130), .7(17)0), 05(101), 0(111), o(TTl), 5(TT2), 



©(TJT1), M(22l). 



