il 
The felspars are microcline and albite in separate erystals 
similar to those of the ægirine-lujavrite. Perthitic intergrowths 
do not occur. In some specimens of the rock both kinds of 
felspar-crystals are present in about equal amounts, other 
specimens abound in microcline, others again contain chiefly 
albite. The felspars are in many cases fresh and transparent, 
in others they have partly been altered to analcime. 
The nepheline and the eudialyte of this rock are quite 
similar to those of the egirine-lujavrite and show the same 
alterations. Sodalite when present as a primary constituent, is 
in rounded grains of the same size as the nepheline-crystals. 
Ægirine in needles similar to those of the ægirine-lujavrite is 
seen in many specimens. 
The arfvedsonite of the arfvedsonite-lujavrite is in elong- 
ated prisms averaging about one millimeter in length. They 
do not show any good crystal outlines but are mostly allo- 
triomorphic. Ortopinacoidal twinning is often observed. The 
absorption-tints are slightly more greenish than those of the 
typical arfvedsonite. The pleochroism-scheme is as follows: — 
a very dark bluish green, 
b deep bluish green (with a faint grayish tone), 
¢ light brownish green. 
In sections parallel to 6 (010) the angle of extinction e:a is 
found to be 10 or 12 degrees!. Not unfrequently the arfved- 
sonite has been partly altered to acmite as described above (see 
p. 137). 
A considerable number of occasional accessories have 
been detected in the arvedsonite-lujavrite, but most of them 
are present only in a few and small crystals, A dark brown 
biotite, small crystals or grains of sphalerite and fluorite, and 
small cubes of pyrochlore?) are not seldom seen, but their 
1 Meddelelser om Grønland XIV, р. 196 (1894). 
