Feb. 1900. New Mineral Occurrences — Farrington. 227 



exceed one millimeter in the direction of greatest length. They are 

 colorless and transparent and remain so with the exception of a 

 slight deliquescence on exposure to air. In distilled water, however, 

 they turn white and in a short time become pulverulent from solution 

 of sodium carbonate. The crystal forms are well developed and the 

 faces fairly sharp and bright. In habit the crystals are somewhat 

 different from any heretofore described on account of the relative 

 subordination of e (on) and the relative greater prominence of r (112) 

 and c (001). 



The following forms were found : 



c (001), m (no), e (on), r (112). 



They were identified by the following measurements : 



No. of 

 Measurements. Limits. Observed. Calculated. 



m:m'"=\\o:\io 5 110° 41 -m° 11 no° 59' 111 10' 



r.-/«=ooi: no 2 83° 25- 83 30' 83 30' 83 30' 



cr=\oo: 112 2 43 13- 43 20' 4^° 20 43° 20' 



<r./=OOl:01I 7 54 10- 54 52' 54° 45' 54° 45' 



e:e' =01 1 : oil 5 108° 59-109 23' 109 23' 109 30' 



r:r'=ii2: 112 2 69 ° 34' 69° 34' 69 29' 



m.'tf=iio:oil 4 42 17- 42 25' 42 25' 42 21' 



e : /— on:Tl2 4 27 22- 27° 29' 27 25' 27 44' 



m : t~ 1 10: 1 12 2 53 10- 53 22' 53 10 53 10' 



The accompanying figure (Fig. 4) shows the usual development 

 of the crystals. This development was quite constant for all that 



Fig. 4— Gay-lussite. 



Fig. 5— Gay-lussite. 



were examined. Fig. 5 shows the same forms in horizontal projec- 

 tion on the plane of the clinopinacoid. Here is better shown, too, the 

 relative greater length of the crystals in the direction of the clinodi- 

 agonal axis. The faces of the prism w (no) are usually duller in 

 lustre than the others, and the basal plane c (001) is often striated 

 parallel to the edge c r. 



