38 



University of California. 



[Vol. 3. 



Habit 4. — The crystals of this habit consist essentially of the 

 prism (110) and a broad steep orthodome (301). The com- 

 bination of these two forms makes a very thin wedge- shaped 

 crystal with sharp edges. Some of the other forms also occur, 

 but they are quite subordinate to these, and do not cause a 

 variation in the habit . The dome (301) has a rounded or wavy 

 surface and seems to grade into a still steeper dome, probably 

 (401) or (601). The form (301) is characteristic of this habit, 

 and was only observed twice on crystals of the other habits. 

 Figure 4, Plate 2, shows this habit with curved edges resembling 

 spear heads. This habit was first described by H. S. Wash- 

 ington.* 



Combinations . — The crystals are so rich in forms that many 

 of them have thirty or more faces. The various combinations 

 observed were as follows: 



1. 



r, 



a, 



t, 



m, k. 



a, I,, W, «A, o-, |8, y, V , d, C, o, f 



■ ) 



b, 



a, 



t, 



m, z, 



k, a ; O", r, (1, J), II. 



3. 



e, 



b, 



a, 



t, m, 



k, It, c, P, y, v, d, .r, o, e, w, 



4. 



a, 



t, 



m 



h, «A, 



1'. (I. 



•). 



b, 



t, 



m, 



y, 



e. y, n, s, p, 17. 



6. 



c, 



b, 



a, 



t, m, 



k, «, h, P, y, v, <], k, o. 



7. 



G, 



b, 



a, 



t, m, 



Z, k, a 5 /? 5 y } y } X, 0, 1. 



8. 



b, 



a, 



t, 



m, z, 



k, a, A, /, y } r, it, o, y, Q. 



!). 



c, 



b, 



t, 



III, K, 



a ; a, /3, y, v, (1, «. 



10. 



c, 



b, 



a, 



t, m, 



«, u ? A, i f Ji f 0", /3 f y f v, <», (1 , C. 



11. 



r 



b, 



a, 



t, m, 



Z. k, a t A, /, c, f$ f y/ ; v, (1, C, 6 



12. 



c, 



b, 



a, 



m, z, 



k, «, i, U, P, y, d, x, e. 



13. 



o, 



b, 



a, 



t, m, 



k, i, It, if*, C, P, f, y, v, «, d . 



14. 



b, 



a, 



t, 



in, A, 



i, W, y, (/, </. y, s, p. 



15. 



b, 



a, 



t, 



m, V, 



h, "A, 6', P. y, v, it, o. 



16. 



c, 



b, 



a, 



t, ni, 



«, «, i, It, P, y, v, o, (t. 



17. 



b, 



m 





H, K 



«, P, tl, X. 



18. 



c, 



b, 



a, 



t, m, 



k 5 a, A, /3, y } r, d, />, o. 



19. 



b, 



t, 



m, 



Z K 



i r , P, y, V, to, r, (1, e. 



20. 



b, 



*, 



m, 



It, \\ 



y, v, d. 



21. 



G, 



b, 



a, 



t, in, 



Z, «, a. o", P, y, V, w, <t , e. 



*H. S. Washington. Amer. Journ. of Science (3), 1887, 34, 281-287 



