PHYSIOGRAPHY. 185 



Sodalite. 



5. It is a valuable ore for the preparation of blue enamel-colors, and 

 particularly for smalt. 



SMARAGDITE. (See Pyroxene.) 

 SOAPSTONE. (See Talc.) 

 SODA-ALUM. (See Solfatarite.) 



SODALITE. Dodecahedral Kouphone-Spar. 



MOHS. 

 Primary form. Rhombic dodecahedron. 



Secondary forms. 



i. 2. 



Primary form, with the acute Cube, with edges 



angles truncated. truncated. 



Lake Laach. Greenland. 



Grains. 







Cleavage, parallel with the primary, with different de- 

 grees of perfection. Fracture conchoidal, uneven. Sur- 

 face even, though sometimes rough. 



Lustre vitreous. Color greyish-black, passing into ash- 

 grey and brown, sometimes a whitish play of light parallel 

 to the planes of the cube, white passing to green and blue, 

 the latter often deep azure-blue. Streak paler than the 

 color. Transparent . . . translucent on the edges. 



Brittle. Hardness -= 5-5 . . . 6-0. Sp. gr. =2-2 . . . 2-3. 



Compound Varieties. Massive : composition granular, 

 individuals strongly connected ; fracture uneven. 



1. The present species consists of what was once believed to constitute 

 four different ones: 1. Lapis-lazuli, the deep azure blue massive va- 

 rieties, commonly found along with massive Iron Pyrites; 2. Hatiyne t 

 crystallized in dodecahedra, and in grains of a bright blue color ; 3. Sod- 

 alite, in white transparent crystals ; 4. Spinellane, in ash-grey and 

 brown crystals. 



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