Gaylussite and Hanhsite from California. 



127 



that, as explorations are carried on, it will be found in other 

 parts of the deposit. 



Crystalline form. — The mineral crystallizes in the ortho- 

 rhombic system and is hemimorphic in its development. The 

 hemim Orphic axis has been taken as the vertical one, and the 

 forms which have been observed are as follows : 



b, 010 

 m, 110 



e, 131 

 jc, 311 



p. 111 

 ^°, 111 



The axial ratio, derived from the measurements marked by 

 an asterisk in the table beyond, is as follows : 



d: 6:c=-56615:l: -3019. 



Although the forms are not numerous the crystals show a 



1. 2. 3. 



considerable variety in habit. Figs. 1 and 2, drawn with 010 

 in front, in order to show the shape better, represent the pre- 

 vailing types. The pyramid e is developed at one extremity 

 of the vertical axis only, and varies much in size. Often e 

 alone terminates the upper end of the crystals, figs. 3 and 6. 

 The pinacoid h is sometimes wanting as represented by figs. 4 

 and 5. The pyramid x was observed on only a single frag- 

 mentary crystal and is not represented in the figures. The 



m 



771 



ra 



crystals vary much in size ; the smaller ones, averaging about 

 5mm ^^ greatest diameter, usually have the habit represented 

 by figs. 1 and 2 ; while the larger ones, sometimes 15°"™ in 

 length, are usually developed like figs. 4 and 5. The larger 



