400 



WHERRY AND ADAMS: PINAVERDOL 



proximately equally developed, d (loi) and D (Toi). In the 

 zone of these domes there are also narrow faces of the base c 

 (ooi). Finally, small faces of the minus unit pyramid U (iii), 

 are usually present. 



Using the upper, orthographic projection of fig. i as a basis, 

 figure 2 has been drawn to show the positions which are occupied 

 by all of the forms observed. Many of these have had to be made 



D 



Fig. 3- Fig- 4- 



Pinaverdol crystals. Habits shown by material of English and German origin. 



relatively much wider than they are in the actual crystals to 

 show them at all. For lettering these forms the plan has been 

 followed of assigning the usual letters, a, b, c, d, and m to the 

 simple forms, and then in any one zone following as far as possible 

 an alphabetical sequence. Thus the several prisms are made 

 successively /, k, I, m, n, o, and p, the plus orthodomes d, e,J, g, 

 and h, the plus unit s, u (iii), and w, the plus orthopyramids 

 a and /S, and the clinodomes a, 8, and e. The minus forms are 

 then named by capital letters corresponding to the small ones of 

 the plus forms. This gives D, E, F, G, H, and / for the ortho- 



