Composition of some Norwegian Minerals. 63 



glucina, zirconia, lanthanium, &c. It was only after I had 

 familiarized myself as much as possible with these substances, 

 that I proceeded to the analysis of a series of the Norwegian 

 minerals which I had collected, paying especial attention to 

 those containing the rare elements ; and as many of the results 

 obtained appeared likely to prove of interest, and some, appa- 

 rently new species, were determined, it is proposed to com- 

 municate them from time to time. 



I. — EUXENITE. 



This mineral was first found by Keilhau at Jolster in 

 Nordre Bergenstift, and was recognised as a distinct species 

 by Scheerer, who analysed it. Some time after a mineral was 

 found by Weibye, near Arendal, supposed to be yttrotantalite, 

 but on analysis by Scheerer (who states Tvedestrand as its 

 locality), was proved to be euxenite.* When Mr Dahl and 

 myself examined this districtf we found two minerals pretty 

 nearly agreeing with Scheerer's description in external ap- 

 pearance, but on further examination they were found to differ 

 greatly from each other ; one, however, found at Alve on Tro- 

 moen, an island near Arendal was evidently the euxenite of 

 Scheerer. 



This we found crystallized in prisms apparently belonging 

 to the rhombic system, and well defined, but, from the faces 

 being rough, and invariably covered by a thin greenish-gray 

 scale, they could not be accurately measured. 



The following measurements taken by Mr Dahl must, there- 

 fore, be considered only as approximative. 



Fig. 1. 



M 



= odP. 

 Fracture conchoidal, with no trace of cleavage ; colour, black ; 



* Poggendorf Annalen, vol. 50, p. 149. 



t JVorsJce Magazin for Naturviclenskab, viii., p. 3. 



s : M = 117° and s : s = 126° 







r ~a, 



m : M = 90° 





v 7" 



r : m = 154° 30' 





V 



T] 



a : r = 159° 30', or 140° 15' 





S 



$ s 



a : M = 107° 









^lso a = P, r = m P co, 









Where mis^l; M — co Poo,moo 



Pco 



J 



s = 



