136 



Molecular ratios 



SiO^ 34,26 0,567 2 



TiO^ 35,15 0, 



ZrO, 11,92 - ^ ^'^^ 



0,99 



),439 \ 



),097 j 



Na^ß 17,12 0,276 I 



Kß ..... 0,37 0,004 I 



Л2О 0,77 



99,59 



If the slight amount of water is neglected, the formula 

 consequently becomes 



Naß • 2(Ti, Zr] 0,^-2 Si 0^ or 



Na.,(TiO].,Si^O,. 



The mineral thus consists of a molecule of sodium meta- 

 silicate Na^SiO-^, and a molecule of orthosilicate of the bivalent 

 group TiO, with part of the titanium replaced by zirconium. 



Structurally tiie formula of the mineral also may be written 



thus 



Na —0 „. rn-r^ 







]\a — 



Lorenzenite has only been found at the locality No. 9 

 on INarsarsuk. The mineral occurred there very sparingly as a 

 secondary formation together with aegirine, microcline, albite, 

 arfvedsonite, elpidite, rhodochrosite, epididymite, polylithionite 

 etc. The aegirine was found in at least two different genera- 

 tions. 1'he crystals of the earliest generation are generally very 

 large and protrude into the drusy cavity from the compact mass 

 of pegmatite. In the cavity they have been subject to an 

 energetic decomposition process. They are traversed by 

 numerous fissures, most of them parallel to the cleavages of 

 the mineral, and along these fissures the decomposition has 

 |)roceeded from the unattached ends of the crystals. Therefore, 



