192 PHYSIOGRAPHY. 



Eudyalite Eukairite. 



Cleavage, parallel to o distinct ; parallel to z less so : 

 traces of cleavage parallel with the faces of the primary 

 rhomboid. Fracture conchoidal or uneven. Surface 

 smooth, but often rather uneven. 



Lustre vitreous. Color brownish-red. Streak white. 

 Translucent on the edges . . . opake. 



Hardness =5-0 . . . 5-5. Sp. gr. =2-898. 



1. Before the blow-pipe, it melts into a leek-green scoria. If redu- 

 ced to powdsr, it gelatinizes with acids. 



2. Analysis. 

 By STROMEYER. 



Silica .... 52-00 



Zhconia . . . 10-89 



Lime .... 10-14 



Soda .... 13-92 



Oxide of iron . 6-85 



Oxide of manganese . . . 2-57 



Muriatic acid . . . . 1-03 



3. It is found in Greenland, mixed with Sodalite,* Hornblende, and 9 

 mountain green variety of Feldspar. 



EUKAIRITE. Selenious Poly poine-Glance 

 Massive : composition granular or impalpable. 

 Lustre metallic. Color lead-grey. Streak white, wher 



impressed with the nail. 



Ductile. Hardness =2-0 . . . 2*5. 



1. When heated alone before the blow-pipe, it emits a strong smell o 

 selenium, and yields greyish white, and hard metallic globules. Heatec 

 with lead upon bone-ashes, it gives a globule of silver. In an open tube 

 it affords a precipitate of selenium and selenious acid. It prevents the 

 reaction of copper with fluxes, and is soluble in nitric acid. 



2. Analysis. 

 By BERZEL.IUS. 



Selenium , . . 31-58 . . . 26-00 

 Silver . . . 43-16 . . . 38-93 



Copper . . . 25-26 , . . 23-05 

 Earthy matters . . 000 . . . 8-90 



