130 



other, neither of them seems to be quite fresh. It looks, further, 

 as if each of the two decomposing minerals contained parts of 

 the other. On one specimen one sees the fracture of a nar- 

 sarsukite table that stands on edge. Only the outer shell of it 

 consists of unaltered mineral. The interior consists of au 

 aggregate of microscopic individuals of other minerals. One of 

 these forms colourless needles which resemble elpidite. They 

 must, however, be another mineral, because they show a con- 

 siderably stronger double refraction than elpidite does. In this 

 aggregate there is a rather large crystal of neptunite which must 

 be presumed to have formed simultaneously with the alteration 

 of the narsarsukite. It looks as if the neptunite crystal during 

 the formation-process had exercised pressure on the remaining 

 covering of undecomposed narsarsukite, both sides of which 

 are curved outwards. If, as it appears from this, the neptunite 

 has been formed at the cost of the narsarsukite, then 

 manganous and ferrous oxides and potash must have been 

 derived from other sources. 



27. Loreuzenite, 



I have named this new mineral after my friend and fellow 

 worker Johan Lorenzen, the Danish mineralogist, who has 

 made numerous important investigations on the minerals of 

 Greenland, and who was taken away by an untimely death 

 while on his way to Greenland in order to study the mode 

 uf occurrence of its minerals. 



Lorenzenite has been found only in the crystallized state. 

 The crystals are needle- like in form and seldom reach more 

 than 1""" in length and 0,1""" in thickness. The diminutive 

 size of the crystals has made their examination a very difficult 

 task;- to procure pure material for the analysis has es[)ecially 

 been attended with much labour. 



