400 MINERALOGY 



Azurite is also radiated, massive, stalactitic, granular, earthy, or 

 botryoidal, with banded concentric layers like malachite, from which 

 such specimens may form by a loss of C0 2 and hydration. 



FIG. 454. Azurite Crystals. Bisbee, Arizona. 



Azurite is a secondary mineral formed from other copper 

 minerals in which the chemical reactions have gone a step farther 

 than in malachite, and some of the C0 2 has been replaced by 

 hydroxyl. 



Azurite is widely distributed in the superficial workings of almost 

 all copper deposits. 



Commercially it is an important ore of copper, and, like malachite, 

 the well-banded and colored specimens are used in the manufacture 

 of trinkets, ornaments, and the less expensive jewelry. 



NATRON 



Natron. Hydrous sodium carbonate, Na 2 COs . 10 H 2 ; 

 Na 2 = 21.7, C0 2 = 15.4, H 2 = 62.9 ; Monoclinic; Type, 

 Equatorial; a : b~ : c == 1.482 : 1 : 1.400; p - 58 52' = 

 001 A 100; 100 A 110 = 51 46'; 001,011=50 10'; Common 

 forms, b (010), m (110), e (Oil) ; Cleavage, basal distinct ; Brittle ; 

 Fracture, conchoidal; H. = 1-1.5; G. = 1.42-1.46; Color, white 



