CARBONATES 401 



ray or yellow ; Streak, white ; Luster, vitreous to dull ; Trans- 

 parent tu r:irtliy. 



B.B. Soluble in water, yielding an alkaline solution; effer- 

 vesces with dilute acids. In the forceps a sodium flame. A strong 

 alkaline taste. 



TRONA 



Trona. Hydrous sodium bicarbonate, Na 3 H(C0 3 ) 2 . 2 H 2 O ; 

 NaaO = 41.2, CO 2 = 38.9, H 2 O = 19.9; Monoclinic; Type, 

 1 :iuatorial ; a : b : 6 = 2.846 : 1 : 2.969 ; P = 77 23' = 001 A 100 ; 

 Common forms, c (001), a (100), o(lll); Cleavage, a perfect; 

 H. = 2.5-3; G. = 2.11-2.14; Color, white, gray, yellowish ; Streak, 

 white; Luster, vitreous; Translucent. 



B.B. Like natron. 



GAYLUSSITE 



Gaylussite. Hydrous sodium calcium carbonate, Na^Ca- 

 (CO 3 ) 2 . 5H 2 O ; CaCOa = 33.8, NajCOa = 35.8, H 2 = 30.4 ; 

 Monoclinic ; Type, Equatorial ; a : b : c = 1.489 : 1 :^.444 ; p 

 = 78 27' = 001 A 100; 100 A 110 = 55 35'; 001 A 101 = 49 

 44'; 001 A Oil = 54 45'; Common forms, c(001), e(011), 

 m(110), r(112); Cleavage, prismatic perfect, basal difficult; 

 Brittle; Fracture, conchoidal; H.= 2-3; G. = 1.93-1.95; Color, 

 white, gray, yellowish; Streak, white; Luster, vitreous; Trans- 

 lucent. 



B.B. Whitens and fuses to a white enamel, yielding an in- 

 tense yellow flame (Na) ; the residue after fusion reacts alkaline 

 with turmeric paper. Soluble in acids with effervescence; the 

 solution made alkaline with ammonia yields a precipitate with 

 ammonium oxalate (Ca). 



General description. Natural soda occurs in numerous 

 localities where the dryness of the climate has permitted the con- 

 centration or complete evaporation of large bodies of saline waters. 

 In the West such deposits occur in Wyoming, Nevada, Utah, and 

 at Mona, Borax, and Owens lakes, California. Most of these 

 localities have been worked commercially for the sodium carbon- 

 ates they contain. It has been estimated by Loew that Owens 



2D 



