232 
quantities of zircon, fluorite, and a rinkite-like mineral have 
been found in one specimen of the rock. 
The apatite in stout prisms or grains is more abundant in 
this rock than in most other nepheline-syenites. The diameter 
of the prisms rarely exceeds 0'1 millimeter. The iron ore is in 
black metallic grains; it occurs in very small quantities and is 
entirely absent in some slices. It is sometimes associated with 
pyrite. 
The principal dark-coloured mineral is ægirine-augite. This 
occurs in very imperfect crystals or allotriomorphic anhedra, 
several millimeters in diameter. It is intensely green with 
marked pleochroism. The extinction angle c:a is large (30° to 
40°) in some specimens, and small (about 20°) in others; 
within each crystal the angle has its maximum value in the 
central portion and decreases towards the margin, but the dif- 
ference is only a few degrees. In one instance an anhedron of 
ægirine-augite has been observed which contained a nucleus 
consisting of colourless diopside with an extinction angle of 
about 45°. 
Hornblende is entirely absent in some specimens, but others 
contain a considerable quantity of it. It is in allotriomorphic 
anhedra. The plane of the optic axis is parallel to (010), and 
the angle of extinction e:c is about 22°; this angle is slightly 
higher in the boundary-zone of the crystals. The pleochroism 
is marked with c dark green, 6 brownish green, and a light 
brown or greenish. 
The biotite is intensely pleochroic; the absorption-tints 
vary from a very dark green (or in some specimens of the 
rock: greenish brown) to a light brownish yellow. It is in 
allotriomorphic plates or aggregates of thick scales. It is 
sometimes found in micrographic intergrowth with the egir- 
ine-augite. As a rule it is in smaller quantities than the 
ægirine-augite, but in two specimens of this rock (from Nia- 
kornarsuk and from the mountain between Giesecke’s Dale 
