128 



the crystal these look like stripes with a well-marked silky 

 lustre, surrounding the central, vitreous part of the crystal. 

 The crystals of this nature, which have been found in this 

 locality, are situated in special cavities and have no marginal 

 faces, but, as typical levynite crystals with the same silk-like 

 layer have been found in West-Greenland and on the drift-ice 

 (as is mentioned below), it is probable that the crystals described 

 above are composed of this mineral. 



Float ice near Iluilek in South-Greenland. In the 

 rock that has already been described under the heading of 

 chabazite, cavities containing levynite also occur. These cry- 

 stals are of rather insignificant size (2 — 3°^"^ in length) and are 

 in the form of very thin plates. They consist of the combin- 

 ation: c{000l}, r{l0ri}, s{022l}, without development of the 

 above-mentioned scalenohedra. Twins about с (oOOl) occur, as 



shown in fig. 11 ; pene- 

 о • : — w-r^ tration-twins which, as 



a rule, are common in 



this mineral are not 



Fie. 11. Levynite; Float ice near Iluilek. n л л mi i 



* found here. The rhom- 



bohedral faces are well-developed and bright; almost without 



any trace of striation. The base is quite plane, but always 



velvet-like and dull and gives no reflex on the goniometer. 



The reason for this is that the face is overlaid by the very 



thin layer of silk-like threads above-described. 



Laumontite. 



This mineral has been found only in a single locality in 

 East-Greenland. 



Henry Land. A basalt-breccia is found near the hot- 

 spring ^) consisting of fragments of a disintegrated greyish-black 

 compact basalt, cemented by a rather incoherent aggregate 



M Mentioned by Haut/ 1. с. page 159. 



i 



