The Mineral Resources of Greenland. 27 
it gave off helium. Later, this fluorspar was proven to be radioactive. 
Hess remarks that the wolframite (variety ferberite) contains nearly 
1 % of columbie and tantalic oxides. 
This pegmatitic mass itself is cut by veins consisting largely of 
quartz and cryolite, and GIESECKE and TAYLER, who examined the 
deposit when the exposures were better, state that this pegmatite is 
also cut by vertical veins of fluorspar from 15—18 cm (6 to 7 inches) 
thick, and TAYLER reports also several thin veins of quartz with some 
cassiterite, felspar, siderite and fluorite. | 
The granite has been altered by intrusion of the pegmatite to a 
rather hard, greenish rock. Originally, it was evidently an aplitic rock 
consisting of irregularly sized grains of orthoclase and oligoclase and less 
quartz. The hard greenish alteration product shows upon microscopic 
examination that much of the felspar has had developed in it many 
small areas of sericite. Cryolite occurs in irregular areas replacing the 
felspar (to a small extent, also probably the quartz) and also in veinlets. 
The granite surrounding all of the cryolite mass is more or less miner- 
alized. 
The cryolite of the pegmatite is undoubtedly a constituent of a 
rock which was deposited by pneumatolytic agencies, presumably of 
granitic, although possibly (see р. 21) of foyaitic origin. The structural 
geologic relations and form indicate this, as does the association with 
such characteristically pegmatitic minerals as microline, quartz, tantalite, 
cassiterite, fluorspar, wolframite, molybdenite, pyrite, and columbite. 
The mineralogic resemblence to certain tin deposits is striking. The 
quartz-cryolite veins are presumably of similar, although somewhat 
later origin, and the cryolite mass itself was presumably deposited by 
the same waters or perhaps by others even more attenuated. 
The cryolite is mined in a great open cut, the vertical walls of 
which stand remarkably well. Air drills are used, and the cryolite is 
shot with black powder down in benches from the top, the effort being 
to shatter the product as little as possible. It is then hand cobbed 
and thrown into wheelbarrows, waste being separated from fairly pure 
eryolite in the process. The cryolite is then wheeled to sorting plat- 
forms where several men scoop water over it; and others hammer off 
impurities and hand sort it. Cryolite only when wet is readily distinguish- 
ed from quartz. 
Three classes of ore result, one for America, the “black” cryolite, 
which is approximately 93 % cryolite, (a bonus is paid the mining 
company for ore over 89 % pure) and two for Denmark, both of white 
cryolite said to be respectively 95 and 99 % pure. The ore is then 
trammed to a hoist and after hoisting is trammed to the pier and placed 
in large, carefully aligned and straight-walled piles according to its 
