3i» 



University of California. 



[Vol. 2. 



;/z(uo) is the predominating form and is represented usually 

 by broad wavy faces. 



<r(ooi) is common, with generally small faces which are charac- 

 teristically striated parallel to the positive pyramidal edges. 



a(ioo) is not very common, and the faces are generally narrow. 



//( ill) and f (ii2) are the common pyramidal forms and are 

 always well developed. 



M(oii) is always present and the faces are long and narrow. 



£•(012) occurs on but few of the crystals, and then as very 

 narrow faces. This is the unit prism of the German mineralogists. 



x(\02) rarely occurs, and the faces are always dull or etched. 



(1. 1. 1 8)? This form was observed on two crystals, as narrow 

 faces. 



Angles measured. Calculated for 



symbol. 



(ooi):(i.i.i8) = 7° 15' 7 35' 



7° 25' 



The base on both crystals was striated and the readings were 

 consequently not perfect enough to place the symbol for the form 

 out of doubt, since the form makes such a small angle with the 

 base. 



The remainder of the forms observed are represented by quite 

 narrow faces, and are of rarer occurrence on the crystals, a large 

 majority of the crystals having the combination m{\ 10), <r(ooi), 

 ti{\ 1 1), f(l 12), and M{p\ 1). Figure 1, PI. 9, shows this combination 

 and also the general habit of the crystals. 



A rarer type is tabular parallel to the base and has a compara- 

 tively broad face of (2(100) in addition to the other forms. This is 

 seen in Figure 2, PI. 9. 



Figure 3, PI. 9, represents a type that is more elongated in the 

 vertical direction, and with some of the narrower forms present. 



Figure 4, PI. 9, shows a more complete combination of forms 

 with the common habit. 



