70 



rich in faces: 5{010}, s{l20}, Ж{110}, Д{210}, w;{30l}, P{lOl}, 

 c{00l}, w{012}, e{02l}, f{Oi\], <t{081}, o{i11}, ä;{411}. 



The faces are generally not so well developed and plain 

 as in the crystals of the principal type, and therefore they are 

 not well adapted to the determination of the axial ratio, in spite 



/W 



M- 



Fig. 15. Ilvaite, type XIV. 



16. Ilvaite, type XIV. 



of the very rich material ; they are generally highly striated in 

 the usual directions, also often more irregularly curved and 

 furrowed. On the other hand the majority of the faces is 

 distinghuished by a peculiarly strong lustre, so that in this 

 respect they surpass all the other forms. 



Type XV 



occupies a special position among the other forms from this 

 region, as well with regard to its way of occurrence as to its 

 form. 



As the preceding type this one is developed in a single 

 mass of pegmatite in the transformed foyaite. The whole mass 

 is about 1 m. in diameter, and the structure is very peculiar. 

 On the outside fine-grained albite is found exclusively; a little 



