PHYSIOGRAPHY. 217 



Gadolinite Galena. 



Compound Varieties. Massive : composition impalpa- 

 ble. Fracture conchoidal. 



1. As soon as the heat of the blow-pipe is communicated to thin 

 fragments, they exhibit an instantaneous glow. In the strongest heat 

 the mass swells up, turns greyish green, and is traversed by numerous 

 fissures. In very thin fragments, it melts with difficulty, into a greyish 

 glass. Some varieties, according to BERZELIUS, become white, and 

 swell into cauliflower-like masses, without suffering fusion ; while oth- 

 ers, according to PHILLIPS, fuse readily, after some decrepitation, into 

 a black glass. 



2. Analysis. 



By BERZELIUS. 



3. Gadolinite occurs in sjneiss and granite, and is chiefly accompanied 

 by Feldspar, Albite and Quartz. Its localities are Ytterby near Stock- 

 holm, and Finbo and Brodbo near Fahlun in Sweden. It is also found 

 in Greenland. 



GAHNITE. (See Jlutomalite.) 

 GALACTITE. 



A name which has been given to a mineral found in the trap/of 

 Kilpatrick, near Glasgow ; but which is probably a variety of 

 Analcime. 



GALAPEKTITE. (See Halloysite.) 

 GALENA. Hexahedral Polypoion e-G lance. 

 Primary form. Cube. 

 Secondary forms. 



1- Cube, with the angles truncated. 

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