Vol. 6] 



Eakle: Neocolemanite. 



183 



by the two faces of a low negative pyramid (223). Other forms 

 are also present on most of the crystals but are much subordinate 

 in size. This habit is shown in figure 4. 



Forms. — Crystals of colemanite from Calico and Death Valley 

 have been described by Jackson 1 and also by the writer- and about 

 fifty forms have been determined for that mineral. The neo- 

 colemanite has eighteen forms and seven of them have no corre- 

 spondence on colemanite. These seven forms are represented by 

 excellent faces and most of them are common for the type. Read- 

 ings were also obtained for other faces from which no satisfactory 

 symbols could be deduced, so they are not included. The forms 

 are arranged in the list below, those not found on colemanite 

 being designated by an asterisk. 





Symbol 



u 



Symbol 



u 



Symbol 



Let 



Gdt. 



Miller 



J 



Gdt. 



Miller 



<u 



J 



Gdt. 



Miller 



c 

 6 

 a 

 t 



m 

 I 







co 

 coO 

 2 co 



CO 

 CO |* 



001 



010 

 100 

 210 

 110 



230 



K 



a 



h 



W 



e 



t 



01 

 02 

 —20 

 —30 

 +24* 

 + 23* 



011 

 021 

 201 

 301 

 241 

 231 







q 



V 



to 







b 



+ 2* 

 - 6* 

 2 



2* 



3 



—21 



29* 



221 

 661 

 221 

 223 

 211 

 263 



The base and front pinacoid are very narrow when present, 

 one of the brown crystals only being an exception, where the 

 6-axis was elongated and the faces were wide. The natural 

 faces of (010) are small and narrow. 



The prism (210) is always a line face. The prism (230) 

 occurs only on the brown crystals and is a common form. 



The clinodome (011) is broad and often has a wavy struc- 

 ture. The dome (021) is a common form only on the brown 

 crystals. 



Of the two negative orthodomes, (301) is fairly common 

 while (201) was observed only on crystals of Habit 2. 



1 A. W. Jackson. On the morphology of Colemanite. Bull. Cal. Acad. Sei., 

 vol. 2 (1885), p. 3. 



2 A. S. Eakle. Colemanite from Southern California. This bulletin, vol. 

 3, no. 2 (1902). 



