GIESECKi:, CRYOLITE OF GREENLAND. 343 



thickness of from 6 to 7 inches. The whole is equally exposed 

 to the tide. The fluor contains no metallic substance, but it is of 

 a singular nature. Its colour is reddish-blue, verging towards 

 lavender-blue ; the substance is dull, soft, and presents rather 

 blunt-edged indeterminably angular fragments. Its powder is 

 reddish-white. It emits a strongly hepatic smell when rubbed. 

 The common kind of compact liuor occurs along with it. 



The cryolite rests upon the gneiss, which contains the sub- 

 stances just enumerated, and forms two distinctly different beds, 

 which are nearly of the same dimensions, namely, 10 fathoms in 

 length, and from 5 to 6 in breadth. The purest cryolite is 

 that of a snow-white colour, without any intermixed foreign sub- 

 stance, if I except a few nearly minute spots of galena. Its 

 colour passes gradually into greyish-white, when it approaches to 

 the other bed. The greyish-white variety on the surface very 

 much resembles ice which has been corroded and grooved by the 

 power of the sun's rays. In these fissures we sometimes observe 

 the threefold cleavage of this substance beautifully displayed. 

 Fragments of quartz and sparry-iron-ore in rhombs sometimes 

 occur in the greyish-white variety. 



The other bed is separated from the former by an elevation of 

 the underlying gneiss, and has a very different appearance. The 

 snow-white and greyish-white colour is. changed gradually into 

 reddish-white, and passes, in proportion to the quantity of im- 

 bedded metallic substances, into orange-yellow and brownish-red. 

 We find in the reddish-white variety quartz crystals and par- 

 ticles of flesh-red felspar ; in the orange-yellow and brownish-red 

 varieties sparry-iron-ore, iron-pyrites, copper-pyrites, and galena 

 occur in great abundance. Sparry-iron-ore occurs massive and in 

 rhomboidal crystals, accumulated in groups of considerable size. 

 Its colour is always dark blackish-brown, and the surface of the 

 crystals partly tarnished, partly decomposed. I found some of the 

 crystals hollow, and some filled with particles of common iron- 

 pyrites. Iron-pyrites occurs generally massive, rarely crystallised 

 in cubes and dodecahedrons. Copper-pyrites occurs only dis- 

 seminated in galena. The galena of this place has the peculiar 

 property of melting caludy before the blowpipe into a globule, 

 without the least decrepitation. Some fragments are covered with 

 a yellowish-white and greenish-white coating, which, when held 

 to a candle, burns with a blue flame and a sulphurous smell. This 

 kind of galena presents some properties of native lead, as the 

 sulphur appears to be elicited, and the ore reduced, by the action 

 of the sea-water or the atmospheric air. Galena occurs here dis- 

 seminated, massive, but rarely crystallised in perfect cubes, and in 

 cubes truncated on the angles and edges. 



This variety of cryolite (I may perhaps call it, in a geological 

 view, metalliferous cryolite) was not known in Europe before I 

 visited the coast of Greenland ; because, owing to its decomposed 

 state, it was not used for any domestic or economical purpose by 

 the Grcenlanders. They preferred the white variety, which, from 

 its colour and greasy appearance, was called by them Orksoksikscet 



