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The lavenite is in imperfect crystals of a brown colour, 
some few millimeters in diameter. As a rule they are more 
abundant than the felspar phenocrysts. In the slices the 
lävenite appears of irregular or rectangular outlines, and con- 
tains numerous inclusions of fluorite, felspar, and ægirine. 
The mineral has been identified by the following observa- 
tions. The mean index of refraction is slightly inferior to 
that of ægirine. The birefringence is about the same as 
that of ægirine. The mineral is optically biaxial and negative 
with an axial angle 2E exceeding 100°. The pleochroism is: 
a light yellow, almost colourless, 
b light yellow, 
¢ deep orange-yellow. 
Sections perpendicular to the optic b-axis show distinct clea- 
vage cracks, and the angle between the a-axis and the direction 
of the cleavage is about 20°. 
Liebenerite-porphyry. 
At several localities within the territory of the Igaliko 
sandstone dykes are found which on account of their outer 
appearance may be characterized as liebenerite-porphyry. They 
are always in a very unfresh condition, but deserve to be 
mentioned because of their close resemblance to the lieben- 
erite-porphyry of Predazzo. Dr. Sreensrrur, in 1875, found a 
dyke of this rock near Igaliko. According to his labels the 
dyke is 1°5 meter wide and the direction is from N. 26° E. 
to S. 26° W. In 1888 he found another, 3 meters wide, dyke 
of the same kind near the former. In 1900 a very wide 
dyke of liebenerite-porphyry was observed on the sea shore 
near Musartut on the western side of the Tunugdliarfik Fjord. 
It is, therefore, not improbable that these dykes, upon con- 
tinued investigations, will prove to be rather common. 
