71 



surface that liave called the attention of the Greenlanders to 

 this mineral occurrence. 



The Liitzen collection consisted mainly of such aegirine 

 crystals that had been isolated through the weathering of the 

 rock. The other minerals in the collection were either such 

 as were implanted on the aegirine crystals or such as probably 

 had only by chance been added to the collection. Thus, aegirine 

 in particular was well represented in this collection. To 

 the description of this mineral that I have previously given, I 

 have, therefore, little to add in this place. 



The aegirine crystals from Narsarsuk are always imper- 

 fect with regard to the character of their faces. The measure- 

 ments that can be performed on them may at most serve for 

 the determination of the different forms, but one cannot use 

 them as a basis for an accurate calculation of the axial ratios 

 of the mineral. There is, however, no reason whatever for 

 supposing that the crystallographical constants of the mineral 

 from this locality should essentially differ from those for aegirine 

 from other localities. For the Norwegian aegirine Brögger 

 has calculated the following axial ratios : 



a:b :c = 1,09753 : 1 : 0,60092 

 ß = 73° 9^1) 



If these axial ratios are retained, the forms observed on the 

 aegirine from Narsarsuk are as follows 



a. = {lOO), b = {OIO}, с {OOl}, m = {uo}, /" = {310}, 

 X = (olo), P = {FOI}, s = {111}, и = {ill}, X = {46l}, 



V = {571}. 



As to the combination of faces the crystals examined are 

 very simple, and all of the enumerated forms are known before 

 as occurring on the Norwegian mineral. The most common 



^) Zeitschr. f. Krystallographie 1890, Vol.16, p. 319. 



