600 MANUAL OF NATURAL HISTORY. 



blue, sub-transparent, sp. gr. 2*21, or " Blue- 

 Vitriol," and many other less important forms. 

 Found in Siberia, at Fahlun in Sweden, in 

 Cornwall, in Australia, and in various parts 

 of America. Symb. Cu. 



4. Family. — Ammoniides. Minerals containing 



compounds of Ammonium. Occur 1, as Oxide 

 or "Ammonia," in small quantities in the 

 atmosphere, smell pungent ; sp. gr. ^ 0*589 ; 

 2, as Chloride or "Sal-ammoniac," as an 

 efflorescence; H. = 1*5-2, sp. gr. = 1*52; 

 whitish ; 3, as Sulphate of Ammonia or 

 " Mascagnine," about volcanoes ; 4, also as 

 Phosphate, Bicarbonate, and combined with 

 with Phosphate of Soda or " Salt of Phos- 

 phorus;" compounds of Ammonium vola- 

 tize with heat, when triturated with mois- 

 tened Hydrate of Oalcia (lime) ammonia is 

 given off. Symb. Am. 



5. Family. — Natrides. Minerals containing com- 



pounds of Sodium. Occur 1, as Sulphate, or 

 "Glauber-Salt," in right prisms, H. 1*5-2, 

 sp.gr. 1-481, white, efflorescent, in thermal 

 springs, &c. ; 2, with Sulphate of Lime, as 

 " Glauberite," in oblique prisms, H. 2*5-3, 

 sp. gr. 2-8, gray, brittle, with rock-salt ; 3, as 

 Nitrate, or "Soda Nitre," rhombohedral, 

 H. 1*5-2, sp. gr. 2*1, white, efflorescent, in 

 Ohili ; 4, as Chloride, or " Common Salt," 

 cubical, H. 2*5, sp. gr. 2*25, white, somewhat 

 brittle and deliquescent, in the ocean, in some 



