Van Name — Crystals of Crocoite from Tasmania. 341 



varied very little upon repeated trial, the position of the base 

 c was interpolated and the angle e^j (001 a 032) was thus 

 found to be 53° 10', calculated 53° 18 7 . On the opposite side 

 of the crystal the clinodome y (021) takes the place of j. 



Another crystal of very similar habit but still more distorted 

 is represented by figure 4. Here again the y face appears on 

 one side only. 



Dauber,* among many previously unrecorded forms for 

 crocoite, mentions but one new clinodome (085), and this he 

 designates as doubtful. Although this index differs but little 

 from (032), the calculated angle upon c (001 ^ 085) is 55° 3', 

 which is nearly two degrees larger than the measured value of 

 C/\j. The index (085) can therefore hardly be assigned to the 

 face^'. Moreover, several other forms whose indices contain 

 the 3 to 2 relation are known to occur upon crocoite. 



The other type of crystal referred to above is the one gener- 

 ally associated with this mineral, short prisms terminated 

 chiefly by the simple pyramids t (111) and v (111) with various 

 modifications. These crystals are usually small and not infre- 

 quently doubly terminated. Two examples are illustrated by 

 figures 5 and 6. Figure 5 represents a very common habit 

 terminated by the pyramids £(111) and ^ (111), and figure 6 



* Loc. cit. 



