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leaving nothing of the original surfaces. This always takes 

 place first on the prismatic faces. One often finds crystals on 

 which the original prismatic faces have totally vanished , while 

 the rhombohedral faces still keep their lustre and have only 

 few etching figures. Simultaneously with the expansion of the 

 etching figures the edges of the crystal are more energetically 

 attacked. Under such circumstances the form of the crystal is 

 quite destroyed, and the result is rounded lumps, which 

 often resemble clear, brilliant hyalite concretions. Such pieces 

 of quartz affected on all sides by solvents occur lying loose in 

 large quantities on Narsarsuk. 



6. Magnetite. 



Of this mineral only a few pieces have been found on 

 Narsarsuk. The place where they were found can not be exactly 

 stated. The largest of the pieces is about the size of a 

 pigeon's egg. Colour pure iron-black; sometimes, however, the 

 mineral shows a bluish tarnish. Fracture conchoidal with 

 metallic lustre. The powder is also of a pure black colour. It 

 is dissolved in hydrochloric acid, leaving a slight residue, which 

 becomes soluble by fusion with potassium bisulphate, and the 

 solution becomes reddish yellow on the addition of hydrogen 

 peroxide; the magnetite is therefore titaniferous. 



The pieces found are for the most part bounded by 

 irregular fractured surfaces , sometimes by surfaces where 

 they have been attached to other minerals. Distinctly deve- 

 loped crystal planes occur only in exceptional cases. The 

 prevailing form is the octahedron, the faces of which are 

 deeply striated parallel to their common combination -edges. 

 As usual with this mineral, the striation is due to the alterna- 

 tion of the faces of the octahedron and those of the rhombic 

 dodecahedron. The latter form is also present as narrow 

 truncations of the edges of the octahedron. These narrow 

 faces are dull and uneven, whereas the faces of the octahedron 



